CN217824654U

CN217824654U - Stator clamp

Info

Publication number: CN217824654U
Application number: CN202221551021.9U
Authority: CN
Inventors: 李伟; 陈世勇; 陈苏苏
Original assignee: Siemens Numerical Control Ltd
Current assignee: Siemens Numerical Control Ltd
Priority date: 2022-06-21
Filing date: 2022-06-21
Publication date: 2022-11-15
Anticipated expiration: 2032-06-21

Abstract

The application discloses stator anchor clamps includes: a tray; the first fixing part and the movable part are arranged on the tray, the inner wall of the first fixing part faces a first direction, the inner wall of the movable part faces a second direction, the second direction is opposite to the first direction, a plurality of arc-shaped grooves are formed in the inner walls of the fixing part and the movable part, the arc-shaped grooves are matched with the profile of the stator, the arc-shaped grooves are arranged in a step shape along the direction perpendicular to the tray, and the diameters of the arc-shaped grooves are gradually increased along the direction far away from the tray; the buffer part comprises an upright post and an elastic piece along a first direction, the first end of the elastic piece is connected with the movable part, the second end of the elastic piece is connected with the upright post, and the upright post is connected to the tray; the movable part can move between the first direction and the second direction under the action of the elastic part so as to clamp the stator in the arc-shaped grooves of the first fixed part and the movable part, wherein the arc-shaped grooves are matched with the diameter of the stator.

Description

Stator clamp

Technical Field

The embodiment of the application relates to the field of tools, in particular to a stator clamp.

Background

The pressing-in of the terminals is a very critical step in the production of the stator of the electrical machine. The terminal need carry out position calibration to the terminal groove of stator before impressing, and position error when the terminal is impressed does not exceed 0.03mm, therefore the terminal position accuracy requirement to the stator before impressing is very high, needs stator anchor clamps can the centre gripping firm, and can not damage the iron core surface. In the prior art, single-station equipment is generally adopted for crimping a motor stator terminal, stators with different outer diameters are generally required to be matched with different clamps, and extra die changing and clamping time can be brought by various clamps in the actual production process. And the stator anchor clamps among the prior art adopt bolt or fixed pin to fasten the stator usually, and this kind of fastening mode operating time is longer and do not control the clamp force well, and the too big meeting of clamp force causes the damage to the stator core surface, and the iron core can not be pressed from both sides tightly completely to the clamp force undersize, causes scrapping of product easily in terminal crimping process, has the potential safety hazard simultaneously.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model is to provide a stator anchor clamps in order to overcome among the prior art the not good control of stator anchor clamps clamp force, the unblock of anchor clamps and press from both sides the defect that the tight process is complicated and need extra remodelling and clamping time.

The utility model discloses a solve above-mentioned technical problem through following technical scheme:

a stator clamp, comprising:

a tray;

the tray comprises a first fixing part and a movable part, wherein the first fixing part and the movable part are arranged on the tray, the inner wall of the first fixing part faces a first direction, the inner wall of the movable part faces a second direction, the second direction is opposite to the first direction, a plurality of arc-shaped grooves are formed in the inner walls of the fixing part and the movable part, the arc-shaped grooves are matched with the profile of a stator, the arc-shaped grooves are arranged in a step shape along the direction perpendicular to the tray, and the diameters of the arc-shaped grooves are gradually increased along the direction far away from the tray;

the buffer part comprises an upright post and an elastic piece along the first direction, the first end of the elastic piece is connected with the movable part, the second end of the elastic piece is connected with the upright post, and the upright post is connected to the tray;

the movable part can move between the first direction and the second direction under the action of the elastic piece so as to clamp the stator in the arc-shaped grooves of the first fixing part and the movable part, wherein the arc-shaped grooves are matched with the diameter of the stator.

The inner walls of the first fixed part and the sliding part of the stator clamp are provided with a plurality of arc-shaped grooves matched with the profiles of the stators with different diameters, so that the stator clamp is suitable for the stators with different shaft heights and diameters, and a large amount of clamp shape changing time is saved; when the clamp is clamped, the elastic piece provides clamping force, and the buffering action of the elastic piece enables the outer iron core of the stator to be uniformly stressed, so that the surface of the iron core is prevented from being damaged during clamping; the utility model discloses a stator anchor clamps's all parts are integrated on the tray for the line of going up of whole set of anchor clamps or roll off the production line very rapidly, thereby reduced the production beat, improved production efficiency.

Optionally, the stator fixture further includes a guide plate, the guide plate is parallel to the tray and connected to the movable portion, a slider is disposed on the guide plate, a slide rail along the first direction is disposed on the tray, and the slider slides on the slide rail to enable the movable portion to move between the first direction and the second direction.

Under the drive of the sliding block, the guide plate drives the movable part to move between the first direction and the second direction, so that the movable part is guaranteed to do linear motion along the first direction (the second direction).

Optionally, a shifting device is arranged on the guide plate, the shifting device is perpendicular to the guide plate, and when the shifting device is shifted by an external cylinder, the movable portion moves in the first direction.

When the stator is put into to needs opening anchor clamps, only need stir this toggle device through the cylinder to open anchor clamps fast, the action is rapid, has promoted production efficiency greatly.

Optionally, a stop block is arranged on the tray, the stop block is located on one side, facing the first direction, of the shifting device, and when the shifting device is shifted by the external cylinder, the stop block limits displacement of the shifting device moving towards the first direction.

When the cylinder stirs the toggle device to open the stator clamp, the stop block can limit the displacement of the toggle device moving towards the first direction, on one hand, the clamp is opened, on the other hand, the phenomenon that the toggle device excessively displaces to cause the elastic piece to excessively stretch so as to generate plastic deformation or fracture failure is avoided, and therefore the service life of the elastic piece is prolonged.

Optionally, the stand is provided with an avoidance hole, and the toggle device and the guide plate can pass through the avoidance hole to move between the first direction and the second direction.

Optionally, the both sides of movable part are equipped with second fixed part and third fixed part respectively, second fixed part inner wall with the inner wall of third fixed part is provided with a plurality of arc walls, the arc wall matches with the stator profile, the arc wall is along the perpendicular to the direction of the upper surface of tray is the echelonment and arranges, the arc wall is along keeping away from the direction diameter of tray increases gradually, the movable part can be followed first direction and slided in order to be in with the stator centre gripping of different diameters first fixed part the second fixed part the third fixed part with in the arc wall of movable part.

The stator is clamped in the arc-shaped grooves of the first fixing part, the second fixing part, the third fixing part and the movable part, and the contact area of the arc-shaped grooves and the outline of the stator is increased, so that the stator is fixed more stably.

Optionally, the first fixing portion, the second fixing portion, the third fixing portion, and the movable portion are fan-shaped cylinders.

Optionally, a circular groove is formed in the middle of the tray, and arc-shaped grooves with the smallest diameters of the first fixing portion, the second fixing portion and the third fixing portion coincide with the inner wall of the circular groove.

On one hand, the circular groove is used as a lightening hole, so that the weight of the stator clamp is reduced, and the material cost is saved; on the other hand, the arc-shaped grooves with the minimum diameters of the first fixing part, the second fixing part and the third fixing part are overlapped with the inner wall of the circular groove, and when the stator fixture is assembled, the inner wall of the circular groove can be used as a reference surface, so that the coaxiality of the first fixing part, the second fixing part and the third fixing part is guaranteed, the assembling precision of the stator fixture is improved, and the positioning precision of the stator fixture is further improved.

Optionally, when the elastic member is in a free state, the arc-shaped groove with the smallest diameter of the movable part exceeds the inner wall of the circular groove along the second direction.

When the elastic member is in a free state, that is, in a state where no external force is applied to the elastic member, the arc-shaped groove having the smallest diameter of the movable portion exceeds the inner wall of the circular groove in the second direction, so that after the stator is placed in the stator fixture, the elastic member is further compressed, thereby uniformly applying elastic force to the outer surface of the stator.

The utility model discloses an actively advance the effect and lie in: the inner walls of the first fixing part and the sliding part of the stator clamp are provided with a plurality of arc-shaped grooves matched with the profiles of stators with different diameters, so that the stator clamp is suitable for stators with different shaft heights and diameters, and a large amount of clamp shape changing time is saved; when the clamp is clamped, the elastic piece provides clamping force, and the buffering action of the elastic piece enables the outer iron core of the stator to be uniformly stressed, so that the surface of the iron core is prevented from being damaged during clamping; the utility model discloses a stator anchor clamps's all parts are integrated on the tray for the line of going up of whole set of anchor clamps or roll off the production line very rapidly, thereby reduced the production beat, improved production efficiency.

Drawings

The drawings are only for purposes of illustrating and explaining the present application and are not to be construed as limiting the scope of the present application.

Fig. 1 shows a front view of a stator clamp according to an embodiment of the present application;

FIG. 2 shows a right side view of a stator clamp according to an embodiment of the present application;

FIG. 3 shows a top view of a stator clamp according to an embodiment of the present application;

FIG. 4 shows a partial cross-sectional view of a stator clamp according to an embodiment of the present application;

FIG. 5 illustrates a partial view of a stator clamp according to an embodiment of the present application;

FIG. 6 shows a schematic view of a stator clamp clamping a larger diameter stator according to an embodiment of the present application;

fig. 7 shows a schematic view of a stator clamp clamping a stator with a smaller diameter according to an embodiment of the application.

Description of reference numerals:

stator clamp 10

First fixed part 111

Second fixed part 112

Third fixed part 113

Movable part 12

Elastic member 13

Upright column 14

Striking mechanism 151

Guide plate 152

Sliding block 153

Slide rail 154

Stop block 16

Tray 17

Circular groove 171

Stator 20 with a large diameter

Stator 30 with a small diameter

Detailed Description

In order to more clearly understand the technical features, objects and effects of the embodiments of the present application, specific embodiments of the present application will be described with reference to the accompanying drawings.

Referring to fig. 1 to 7, wherein fig. 1 illustrates a front view of a stator clamp according to an embodiment of the present application, fig. 2 illustrates a right view of the stator clamp according to the embodiment of the present application, fig. 3 illustrates a top view of the stator clamp according to the embodiment of the present application, fig. 4 illustrates a partial view of the stator clamp according to the embodiment of the present application, fig. 5 illustrates a partial sectional view of the stator clamp according to the embodiment of the present application, fig. 6 illustrates a schematic view of the stator clamp according to the embodiment of the present application clamping a stator having a large diameter, and fig. 7 illustrates a schematic view of the stator clamp according to the embodiment of the present application clamping a stator having a small diameter.

As shown in fig. 1, the stator holder 10 of the present embodiment includes a tray 17, a first fixing portion 111, a movable portion 12, and a buffer portion. Wherein, first fixed part 111 and movable part 12 are located on tray 17, the inner wall of first fixed part 111 is towards first direction (left side in fig. 1), the inner wall of movable part 12 is towards the second direction (right side in fig. 1), the inner wall of first fixed part 111 and the inner wall of movable part 12 are provided with a plurality of arc walls, these arc walls match with the stator profile respectively, the arc walls are the echelonment along the direction (vertical direction in fig. 1) of perpendicular to tray 17 and arrange, the arc walls is along keeping away from tray 17's direction diameter increase gradually. As shown in fig. 1, the stator clamp 10 further includes a buffer portion including a pillar 14 and an elastic member 13 along a first direction, a first end of the elastic member 13 is connected to the movable portion 12, a second end of the elastic member 13 is connected to the pillar 14, and a lower end of the pillar 14 is connected to the tray 17. The movable portion 12 is movable between a first direction and a second direction by the elastic member 13, and when the movable portion 12 is moved to the first direction to open the stator holder 10, the stator is placed in the arc-shaped groove matching with the profile of the stator, and then the movable portion 12 is moved to the second direction by the elastic member 13 to clamp the stator in the arc-shaped grooves matching with the profile of the stator of the first fixing portion 111 and the movable portion 12.

The inner walls of the first fixed part 111 and the movable part 12 of the stator clamp 10 are provided with a plurality of arc-shaped grooves matched with the profiles of stators with different diameters, so that the stator clamp is suitable for stators with different shaft heights and diameters, and a large amount of clamp model changing time is saved; when the clamp is clamped, the elastic piece 13 provides clamping force, and the buffering action of the elastic piece 13 enables the stator outer iron core to be uniformly stressed, so that the surface of the stator is prevented from being damaged during clamping; all the components of the stator clamp 10 are integrated on the tray 17, so that the whole set of clamps can be quickly loaded or unloaded, the production takt is reduced, and the production efficiency is improved.

In this embodiment, the elastic member 13 is a spring, and in other embodiments, other types of elastic members 13 can be used.

As shown in fig. 3, 2 elastic members 13 are symmetrically arranged along the length direction of the column 14 so as to uniformly apply elastic force to the movable part 12.

As shown in fig. 1, the stator clamp 10 further includes a guide plate 152, the guide plate 152 is parallel to the tray 17 and is connected to the movable portion 12, a sliding block 153 is disposed on the guide plate 152, a sliding rail 154 along the first direction is disposed on the tray 17, and the sliding block 153 slides on the sliding rail 154 to move the movable portion 12 between the first direction and the second direction. Under the driving of the sliding block 153, the guide plate 152 drives the movable portion 12 to move between the first direction and the second direction, so as to ensure that the movable portion 12 moves linearly along the first direction (the second direction).

As shown in fig. 1, a toggle device 151 is disposed on the guide plate 152, the toggle device 151 is perpendicular to the guide plate 152, and when the toggle device 151 is toggled by an external cylinder, the movable portion 12 moves in a first direction. When stator fixture 10 needs to be opened and put into the stator, the shifting device 151 only needs to be shifted through the cylinder, so that the fixture is quickly opened, the action is rapid, and the production efficiency is greatly improved.

In this embodiment, the toggle device 151 is T-shaped, as shown in fig. 4-5. The T-shaped toggle device 151 comprises a wing plate of a transverse part and a web plate of a longitudinal part, a hole for allowing the web plate to pass through is formed on the guide plate 152, and the wing plate and the guide plate 152 are fixed in a vertical direction by using a fastener. When the clamp needs to be opened, the web portion of the toggle device 151 needs to be toggled only by the air cylinder, so that the slide block 153 on the guide plate 152 moves along the slide rail 154 in the first direction under the driving of the toggle device 151, and the movable portion 12 is driven to move in the first direction to open the stator clamp 10.

As shown in fig. 1, 3 and 5, the tray 17 is provided with a stop block 16, the stop block 16 is located on one side of the toggle device 151 facing the first direction, i.e. the left side of the toggle device 151 in the figure, and when the external cylinder toggles the toggle device 151, the stop block 16 limits the displacement of the toggle device 151 moving to the first direction.

When the cylinder stirs the toggle device 151 to open the stator clamp 10, the stop block 16 can limit the displacement of the toggle device 151 moving towards the first direction, on one hand, the clamp is opened, and on the other hand, the phenomenon that the elastic part 13 is excessively compressed to generate plastic deformation or fracture failure due to the excessive displacement of the toggle device 151 is avoided, so that the service life of the elastic part 13 is prolonged.

As shown in fig. 2, the elastic member 13 is connected to an upper portion of the column 14, a relief hole is formed in a lower middle portion of the column 14, the relief hole extends from the tray 17 to a position above the toggle device 151, and the toggle device 151 and the guide plate 152 can move between the first direction and the second direction through the relief hole, so that the elastic member 13, the column 14, the toggle device 151, the guide plate 152, and the like can be reasonably arranged by fully utilizing a high space, and the structure of the stator fixture 10 is more compact.

As shown in fig. 2 and 3, the two sides of the movable portion 12 are respectively provided with a second fixing portion 112 and a third fixing portion 113, the inner walls of the second fixing portion 112 and the third fixing portion 113 are provided with a plurality of arc-shaped grooves, the arc-shaped grooves are matched with the profile of the stator, the arc-shaped grooves are arranged in a step shape along the direction perpendicular to the upper surface of the tray 17, the diameters of the arc-shaped grooves are gradually increased along the direction away from the tray 17, and the movable portion 12 can slide along the first direction to clamp stators with different diameters in the arc-shaped grooves of the first fixing portion 111, the second fixing portion 112, the third fixing portion 113 and the movable portion 12.

When the stator clamp 10 clamps the stator, the stator is clamped in the arc-shaped grooves of the first fixing portion 111, the second fixing portion 112, the third fixing portion 113 and the movable portion 12, increasing the contact area of the arc-shaped groove of the stator clamp 10 with the profile of the stator, thereby making the stator clamped more stable.

As shown in fig. 3, the first fixing portion 111, the second fixing portion 112, the third fixing portion 113, and the movable portion 12 are fan-shaped columns. The arc-shaped grooves are arranged in a ladder shape along the inner walls of the first fixing part 111, the second fixing part 112, the third fixing part 113 and the movable part 12 of the fan-shaped column body, and the diameter of the arc-shaped grooves is gradually increased along the direction far away from the tray 17. As shown in fig. 3, the larger the diameter of the arc-shaped groove is, the larger the area of the arc-shaped surface of the arc-shaped groove in contact with the stator is, and the smaller the diameter of the arc-shaped groove is, the smaller the area of the arc-shaped surface of the arc-shaped groove in contact with the stator is. That is, when the stator jig 10 fastens the stator 30 having a small diameter, as shown in fig. 7, the area of the arc-shaped groove where the stator jig 10 contacts with the stator is relatively small; when the stator clamp 10 fastens the stator 20 with a larger diameter, as shown in fig. 6, the area of the arc-shaped groove of the stator clamp 10 contacting with the stator is relatively larger, that is, the area of the arc-shaped groove contacting with the stator is matched with the diameter of the stator, so that the stator clamp has a better fastening effect for stators with different diameters.

As shown in fig. 3, a circular groove 171 is disposed in the middle of the tray 17, the arc-shaped grooves with the smallest diameter of the first fixing portion 111, the second fixing portion 112, and the third fixing portion 113 coincide with the inner wall of the circular groove 171, that is, the arc-shaped grooves of the first fixing portion 111, the second fixing portion 112, and the third fixing portion 113 are coaxial with the circular groove 171, and the arc-shaped grooves with the smallest diameter of the first fixing portion 111, the second fixing portion 112, and the third fixing portion 113 are the same as the diameter of the circular groove 171

On one hand, the circular groove 171 serves as a lightening hole, so that the weight of the stator clamp 10 is reduced, and the material cost is saved; on the other hand, the arc-shaped grooves with the smallest diameter of the first fixing portion 111, the second fixing portion 112, and the third fixing portion 113 are overlapped with the inner wall of the circular groove 171, and when the stator fixture 10 is assembled, the inner wall of the circular groove 171 can be used as a reference surface, so that the coaxiality of the first fixing portion 111, the second fixing portion 112, and the third fixing portion 113 is ensured, the assembly precision of the stator fixture 10 is improved, and the positioning precision of the stator fixture 10 is further improved.

As shown in fig. 3, when the elastic member 13 is in the free state, the arc-shaped groove of the movable portion 12 having the smallest diameter exceeds the inner wall of the circular groove 171 in the second direction. When the elastic member 13 is in a free state, i.e., in a state where no external force is applied to the elastic member 13, the elastic member 13 is in a first compressed state, and the arc-shaped groove with the smallest diameter of the movable portion 12 exceeds the inner wall of the circular groove 171 in the second direction; after the stator is placed in the stator fixture 10, the movable portion 12 is coaxial with the first fixing portion 111, the second fixing portion 112, the third fixing portion 113 and the circular groove 171, that is, the arc-shaped groove with the smallest diameter of the movable portion 12 coincides with the inner wall of the circular groove 171, and the elastic member 13 is in a second compression state, wherein the compression amount of the second compression state is greater than that of the first compression state, so that the elastic force is uniformly applied to the outer surface of the stator.

When the elastic element 13 is in a free state, i.e. in a state where no external force is applied to the elastic element 13, the arc-shaped groove with the smallest diameter of the movable portion 12 exceeds the inner wall of the circular groove 171 in the second direction, the toggle device 151 and the stop block 16 are not in contact, and the elastic element 13 is in the first compressed state. When the web of the toggle device 151 is toggled towards the first direction by the external cylinder, the toggle device 151 drives the connecting plate, the sliding block 153 and the movable part 12 to move towards the first direction until the toggle device 151 contacts with the stop block 16, at this moment, the clamp is opened, the elastic part 13 is compressed more, and at this moment, the stators with different outer diameters can be horizontally placed on the arc-shaped grooves corresponding to the first fixing part 111, the second fixing part 112, the third fixing part 113 and the movable part 12. After the external cylinder retracts, under the elastic force of the elastic element 13, the movable portion 12 moves towards the second direction, the shifting device 151 and the connecting plate are driven to move towards the second direction, the sliding block 153 slides towards the second direction on the sliding rail 154 to ensure that the movable portion 12 makes linear motion along the second direction, finally the stator is clamped tightly, at the moment, the arc-shaped groove with the minimum diameter of the movable portion 12 coincides with the inner wall of the circular groove 171, and the elastic element 13 is in a second compression state.

It should be understood that although the specification has been described in terms of various embodiments, not every embodiment includes every single embodiment, and such description is for clarity purposes only, and it will be appreciated by those skilled in the art that the specification as a whole can be combined as appropriate to form additional embodiments as will be apparent to those skilled in the art.

The above description is only an exemplary embodiment of the present disclosure, and is not intended to limit the scope of the present disclosure. Any person skilled in the art should also understand that they can make equivalent changes, modifications and combinations without departing from the concept and principle of the embodiments of the present application.

Claims

1. A stator clamp, comprising:

a tray (17);

the stator comprises a first fixing part (111) and a movable part (12), wherein the first fixing part (111) and the movable part (12) are arranged on the tray (17), the inner wall of the first fixing part (111) faces a first direction, the inner wall of the movable part (12) faces a second direction, the second direction is opposite to the first direction, a plurality of arc-shaped grooves are formed in the inner walls of the fixing part and the movable part (12), the arc-shaped grooves are matched with the profile of a stator, the arc-shaped grooves are arranged in a step shape along the direction perpendicular to the tray (17), and the diameters of the arc-shaped grooves are gradually increased along the direction far away from the tray (17);

the buffer part comprises an upright post (14) and an elastic piece (13) along the first direction, a first end of the elastic piece (13) is connected with the movable part (12), a second end of the elastic piece (13) is connected with the upright post (14), and the upright post (14) is connected to the tray (17);

the movable part (12) can move between the first direction and the second direction under the action of the elastic piece (13) so as to clamp the stator in the arc-shaped grooves of the first fixing part (111) and the movable part (12) matched with the diameter of the stator.

2. The stator clamp according to claim 1, characterized in that it further comprises a guide plate (152), said guide plate (152) being parallel to said tray (17) and being connected to said movable portion (12), said guide plate (152) being provided with a slide (153), said tray (17) being provided with a slide rail (154) along said first direction, said slide (153) sliding on said slide rail (154) to move said movable portion (12) between said first direction and said second direction.

3. The stator fixture according to claim 2, wherein a toggle device (151) is provided on the guide plate (152), the toggle device (151) is disposed perpendicular to the guide plate (152), and when the toggle device (151) is toggled by an external cylinder, the movable portion (12) moves to the first direction.

4. A stator clamp according to claim 3, characterized in that a stop block (16) is arranged on the tray (17), the stop block (16) is located at a side of the toggle device (151) facing the first direction, and the stop block (16) limits the displacement of the toggle device (151) towards the first direction when the external cylinder toggles the toggle device (151).

5. Stator clamp according to claim 4, characterized in that said upright (14) is provided with an escape hole through which said toggle device (151) and said guide plate (152) can move between said first direction and said second direction.

6. The stator clamp according to any of claims 1-5, characterized in that the two sides of the movable part (12) are respectively provided with a second fixing part (112) and a third fixing part (113), the inner wall of the second fixing part (112) and the inner wall of the third fixing part (113) are provided with a plurality of arc-shaped grooves, the arc-shaped grooves match with the stator profile, the arc-shaped grooves are arranged in a step shape along the direction perpendicular to the upper surface of the tray (17), the diameter of the arc-shaped grooves gradually increases along the direction away from the tray (17), and the movable part (12) can slide along a first direction to clamp stators with different diameters in the arc-shaped grooves of the first fixing part (111), the second fixing part (112), the third fixing part (113) and the movable part (12).

7. The stator clamp according to claim 6, characterized in that the first fixing portion (111), the second fixing portion (112), the third fixing portion (113), the movable portion (12) are fan-shaped columns.

8. The stator clamp according to claim 7, characterized in that the tray (17) is provided with a circular groove (171) in the middle, and the arc-shaped grooves with the smallest diameter of the first fixing portion (111), the second fixing portion (112) and the third fixing portion (113) coincide with the inner wall of the circular groove (171).

9. The stator clamp according to claim 8, characterized in that the arc-shaped groove of the movable part (12) having the smallest diameter exceeds the inner wall of the circular groove (171) in the second direction when the elastic member (13) is in the free state.