CN219969361U - Vehicle with sliding door - Google Patents

Abstract

The embodiment of the utility model provides a vehicle with a sliding door, which comprises the following components: a roof including opposing first and second surfaces, and two doors; wherein one of the vehicle doors is movably connected to the first surface of the vehicle roof, and the other vehicle door is movably connected to the second surface of the vehicle roof; the vehicle doors are switched between an open state and a closed state, and are respectively arranged on two opposite sides of the vehicle roof under the condition that the two vehicle doors are in the closed state; under the condition that two car doors are in the open state, one car door is attached to the first surface of the car roof, the other car door is attached to the second surface of the car roof, and the car roof is clamped between the two car doors, so that the car can get on or off conveniently.

Description

Vehicle with sliding door

Technical Field

The utility model relates to the technical field of vehicles, in particular to a vehicle with a sliding door.

Background

The car door is one of the main parts of the car body, and the opening and closing modes of the car door directly influence the usability and the user experience of the car. Currently, automobile doors mainly include front opening doors, side-by-side doors, scissor doors, gull-wing doors, eagle-wing doors, butterfly doors, swing doors, seat doors, sunroof doors, and the like.

However, these types of doors occupy a certain door opening or a large space, thereby causing inconvenience to users in getting on and off the vehicle.

Disclosure of Invention

The embodiment of the utility model provides a vehicle with a sliding door, which aims to solve the problem that the door occupies a certain door opening or a larger space, so that a user cannot get on or off the vehicle conveniently.

In order to solve the above problems, an embodiment of the present utility model discloses a vehicle having a sliding door, including: a roof including opposing first and second surfaces, and two doors; wherein,

one of the vehicle doors is movably connected to the first surface of the vehicle roof, and the other vehicle door is movably connected to the second surface of the vehicle roof;

the vehicle doors are switched between an open state and a closed state, and are respectively arranged on two opposite sides of the vehicle roof under the condition that the two vehicle doors are in the closed state; and under the condition that the two vehicle doors are in the open state, one vehicle door is attached to the first surface of the vehicle roof, the other vehicle door is attached to the second surface of the vehicle roof, and the vehicle roof is clamped between the two vehicle doors.

Optionally, a rack structure is arranged on one side of the vehicle door facing the vehicle roof, and a gear is arranged on one side of the vehicle roof facing the vehicle door;

the rack structure extends along the moving direction of the vehicle door;

the gear is correspondingly arranged with the rack structure, and is meshed with the corresponding rack structure, so that the vehicle door is movably connected with the vehicle roof.

Optionally, the rack structure is disposed at a middle position of the vehicle door.

Optionally, a first guide piece is arranged on one side of the vehicle door facing the vehicle roof, and a second guide piece is arranged on one side of the vehicle roof facing the vehicle door;

the first guide piece is in limit fit with the second guide piece, and the first guide piece and the second guide piece are connected in a sliding mode along the moving direction of the vehicle door.

Optionally, the first guide piece is a guide groove, and the corresponding second guide piece is a guide post;

or, the first guide piece is a guide post, and the corresponding second guide piece is a guide groove;

the guide groove extends along the moving direction of the vehicle door, and the guide post is embedded in the guide groove and is connected with the guide groove in a sliding mode.

Optionally, the first guide piece is a guide groove, and the corresponding second guide piece is a guide post;

two guide grooves are respectively formed in the two opposite sides of the rack structure;

the rack structure is parallel to the guide groove and is arranged at intervals.

Optionally, the number of the rack structures is two;

the two rack structures are symmetrically arranged on two sides of the vehicle door.

Optionally, the vehicle comprises a drive;

the driving piece is arranged on the vehicle roof;

the driving piece is arranged corresponding to the gear, and the driving piece is used for driving the corresponding gear to move along the rack structure.

Optionally, the vehicle comprises a cockpit;

an operation button is arranged in the cockpit;

the operation button is electrically connected with the driving piece through a wire harness and is used for adjusting the working state of the driving piece.

Optionally, the vehicle door is of an arc structure, and the corresponding first surface and second surface are arc surfaces.

The embodiment of the utility model has the following advantages:

in the embodiment of the utility model, the vehicle roof comprises a first surface and a second surface which are opposite, when both the vehicle doors are in an open state, one of the vehicle doors can be attached to the first surface of the vehicle roof, the other vehicle door can be attached to the second surface of the vehicle roof, and the vehicle roof is clamped between the two vehicle doors, so that under the condition of opening the vehicle doors, the vehicle doors can be positioned at the top of the vehicle and are completely opened, the vehicle doors are prevented from occupying the space of the opening of the vehicle doors, so that the opening of the vehicle doors can have a larger space, and a user can get on or off the vehicle conveniently.

Drawings

FIG. 1 is a schematic view of a vehicle door in a closed position according to an embodiment of the present utility model;

FIG. 2 is a schematic view of a vehicle door in an open position according to an embodiment of the present utility model;

FIG. 3 is a schematic illustration of a door and roof mating configuration in an embodiment of the present utility model;

FIG. 4 is a schematic view showing a structure of a vehicle in a door-closed state according to an embodiment of the present utility model;

fig. 5 is a schematic view showing a structure in which a vehicle is in a door-open state in an embodiment of the present utility model.

Reference numerals illustrate:

1-roof, 11-first surface, 2-door, 21-first side door, 22-second side door, 31-gear, 32-rack structure, 4-guide slot, 5-driving piece, 6-body, 7-base, 8-wheel.

Detailed Description

In order that the above-recited objects, features and advantages of the present utility model will become more readily apparent, a more particular description of the utility model will be rendered by reference to the appended drawings and appended detailed description.

The features of the utility model "first", "second" and the like in the description and in the claims may be used for the explicit or implicit inclusion of one or more such features. In the description of the present utility model, unless otherwise indicated, the meaning of "a plurality" is two or more. Furthermore, in the description and claims, "and/or" means at least one of the connected objects, and the character "/", generally means that the associated object is an "or" relationship.

In the description of the present utility model, it should be understood that the terms "center," "length," "width," "left," "right," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate description of the present utility model and simplify the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be configured and operated in a particular orientation, and thus should not be construed as limiting the present utility model.

In the description of the present utility model, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

One of the key ideas of the embodiments of the present utility model is to disclose a vehicle with a sliding door, as shown in fig. 1 and 3, which may specifically include: a roof 1 and two doors 2, the roof 1 may include opposing first and second surfaces 11, 2; wherein one door 2 can be movably connected to the first surface 11 of the vehicle roof 1, and the other door 2 can be movably connected to the second surface of the vehicle roof 1; the vehicle door 2 is switched between an open state and a closed state, and in the case where both the vehicle doors 2 are in the closed state, as shown in fig. 3, both the vehicle doors 2 are provided on opposite sides of the roof 1, respectively; in the case where both doors 2 are in the open state, one door 2 is attached to the first surface 11 of the roof 1, the other door 2 is attached to the second surface of the roof 1, and the roof 1 is sandwiched between both doors 2 as shown in fig. 5.

In the embodiment of the present utility model, the vehicle roof 1 includes a first surface 11 and a second surface opposite to each other, in the open state of both the vehicle doors 2, one of the vehicle doors 2 may be attached to the first surface 11 of the vehicle roof 1, the other vehicle door 2 may be attached to the second surface of the vehicle roof 1, and the vehicle roof 1 is clamped between the two vehicle doors 2, so that, in the open state of the vehicle doors 2, the vehicle doors 2 may be located at the top of the vehicle and fully opened, so that the vehicle doors 2 are prevented from occupying the space of the opening of the vehicle doors 2, so that the opening of the vehicle doors 2 may have a larger space, and a user may get on or off the vehicle conveniently.

The vehicle in the embodiment of the utility model can be specifically an automobile, a passenger car, a truck and the like, and can be specifically set according to actual requirements, and the embodiment of the utility model is not particularly limited.

Specifically, as shown in fig. 1 and 2, the vehicle may include a roof 1, a base 7, a body 6, wheels 8, and the like; the vehicle roof 1 can be arranged at the top of the vehicle body 6, the base 7 can be arranged at the bottom of the vehicle body 6, and the vehicle roof 1, the base 7, the vehicle door 2 and the vehicle body 6 can be enclosed to form a passenger cabin; the wheels 8 may be fixedly attached to the side of the base 7 remote from the body 6.

In particular, the roof 1 may comprise a first surface 11 and a second surface opposite, the first surface 11 of the roof 1 may be located outside the vehicle, and the second surface of the roof 1 may be located inside the vehicle; alternatively, the first surface 11 of the roof 1 may be located inside the vehicle, and the corresponding second surface of the roof 1 may be located outside the vehicle, which may be specifically set according to actual requirements, which is not specifically limited in the embodiment of the present utility model.

Specifically, the vehicle may further include two doors 2, wherein one door 2 may be movably connected to the first surface 11 of the roof 1, and the other door 2 may be movably connected to the second surface of the roof 1; the door 2 can be switched between an open state and a closed state, and the door 2 can be overlapped with the roof 1 when the door 2 is in the open state; with the door 2 in the closed state, the door 2 can be unfolded with respect to the roof 1.

Specifically, as shown in fig. 3, the two doors 2 may include a first side door 21 and a second side door 22; the first side door 21 may be movably coupled to the first surface 11 of the roof 1, and the second side door 22 may be movably coupled to the second surface of the roof 1. The first side door 21 may be a left side door, and the corresponding second side door 22 may be a right side door, or the first side door 21 may be a right side door, and the corresponding second side door 22 may be a left side door, which may be specifically set according to actual requirements, which is not specifically limited in the embodiment of the present utility model.

Specifically, as shown in fig. 3, the first side door 21 and the second side door 22 are both in a closed state, the first side door 21 and the second side door 22 are both unfolded from the roof 1, and the first side door 21 and the second side door 22 are respectively disposed on opposite sides of the roof 1. As shown in fig. 5, the first side door 21 and the second side door 22 are both in an open state, the first side door 2 and the second side door 2 are both located at the top of the vehicle, the first side door 21 is attached to the first surface 11 of the roof 1, the second side door 22 is attached to the second surface of the roof 1, and the roof 1 is clamped between the first side door 21 and the second side door 22, so that the first side door 21 and the second side door 22 are both completely opened, a user can get on or off the vehicle conveniently, and under the condition that the first side door 21 and/or the second side door 22 are in an open state, the first side door 21 and/or the second side door 22 can be hidden at the top of the vehicle, so that the opened first side door 21 or second side door 22 can be prevented from occupying an external space, and further, a collision caused by a collision by a accident can be avoided, and the safety of getting on or off the vehicle by the user can be improved.

Specifically, the first side door 21 and the second side door 22 may be opened and closed independently of each other, or may be opened and closed synchronously, which may be specifically set according to actual requirements, which is not specifically limited in the embodiment of the present utility model.

Alternatively, the side of the door 2 facing the roof 1 may be provided with a rack structure 32, and the side of the roof 1 facing the door 2 may be provided with a gear 31; the rack structure 32 may extend in the moving direction of the door 2; the gear 31 may be disposed corresponding to the rack structure 32, and the gear 31 may be engaged with the corresponding rack structure 32, so as to implement the movable connection of the vehicle door 2 to the vehicle roof 1.

In the embodiment of the utility model, the rack structure 32 is arranged on one side of the vehicle door 2 facing the vehicle roof 1, and the gear 31 is arranged on one side of the vehicle roof 1 facing the vehicle door 2, and the rack structure 32 extends along the moving direction of the vehicle door 2, so that the vehicle door 2 is conveniently and movably connected to the vehicle roof 1 through the meshing connection of the gear 31 and the rack structure 32, and the vehicle door 2 is conveniently opened and closed.

Specifically, the second side door 22 is described as an example with reference to fig. 4: the side of the second side door 22 facing the first surface 11 of the roof 1 is provided with a rack structure 32, and the rack structure 32 extends along the length direction of the second side door 22, the first surface 11 of the roof 1 is provided with a gear 31, and the gear 31 is engaged with the rack structure 32, so that the second side door 22 can be opened or closed along the length direction thereof.

Specifically, the opening and closing manner of the first side door 21 is the same as the opening and closing manner of the second side door 22, and the embodiments of the present utility model will not be repeated.

Alternatively, the rack structure 32 may be provided at an intermediate position of the door 2.

In the embodiment of the utility model, the rack structure 32 is arranged at the middle position of the vehicle door 2, so that the stress of the vehicle door 2 is relatively balanced in the process of meshing and connecting the gear 31 and the rack structure 32, and the reliability and stability of switching the vehicle door 2 between the open state and the closed state can be improved.

Specifically, as shown in fig. 3, the rack structure 32 may be provided at an intermediate position of the door 2 in the width direction of the door 2, and both sides of the door 2 in the width direction are forced to be balanced when the door 2 is switched between the open state and the closed state.

Alternatively, the side of the door 2 facing the roof 1 may be provided with a first guide and the side of the roof 1 facing the door 2 may be provided with a second guide; the first guide member may be in a limit fit with the second guide member, and the first guide member and the second guide member may be slidably connected in the moving direction of the door 2.

In the embodiment of the utility model, the first guide piece is in limit fit with the second guide piece, and the first guide piece and the second guide piece are connected in a sliding manner along the moving direction of the vehicle door 2, so that under the cooperation of the first guide piece and the second guide piece, the moving path of the vehicle door 2 relative to the vehicle roof 1 can be limited, the gear 31 is effectively ensured to be meshed along the rack structure 32, and the switching reliability of the vehicle door 2 between the open state and the closed state is further improved.

Alternatively, the first guide may be a guide groove 4 and the corresponding second guide may be a guide post; alternatively, the first guide may be a guide post and the corresponding second guide may be a guide slot 4; the guide groove 4 may extend along the moving direction of the vehicle door 2, and the guide post may be embedded in the guide groove 4 and slidably connected to the guide groove 4.

In the embodiment of the utility model, the guide groove 4 extends along the moving direction of the vehicle door 2, and the guide post is embedded in the guide groove 4 and is slidably connected to the guide groove 4, so that the guide groove 4 can limit the guide post to move only along the moving direction of the vehicle door 2, and the reliability of switching the vehicle door 2 between the open state and the closed state can be further improved.

In particular, as shown in fig. 3, in the case where the guide groove 4 is provided in the door 2, other cases may be referred to, and the embodiment of the present utility model is not particularly limited thereto.

Alternatively, as shown in fig. 3, the first guide member is a guide groove 4, and the corresponding second guide member is a guide post; two guide grooves 4 may be provided on opposite sides of the rack structure 32, respectively; the rack structure 32 may be disposed parallel to and spaced apart from the guide groove 4.

In the embodiment of the utility model, two guide grooves 4 are respectively arranged on two opposite sides of the rack structure 32, so that in the process of meshing and connecting the gear 31 and the rack structure 32, the two guide posts can slide along the corresponding guide grooves 4, the door 2 can be prevented from moving relative to the roof 1 along the width direction, the meshing stability of the gear 31 along the rack structure 32 is improved, and the switching reliability of the door 2 between the open state and the closed state is further improved.

Alternatively, the number of rack structures 32 may be two; the two rack structures 32 may be symmetrically disposed on both sides of the door 2.

In the embodiment of the utility model, the two rack structures 32 are symmetrically arranged at two sides of the vehicle door 2, so that in the process of respectively meshing the two gears 31 along the corresponding rack structures 32, the two sides of the vehicle door 2 can be driven to move simultaneously, so that the stress at the two sides of the vehicle door 2 is balanced, and the reliability and stability of the movement of the vehicle door 2 relative to the vehicle roof 1 can be improved.

Specifically, the gears 31 are arranged in a one-to-one correspondence with the rack structures 32, and in the case that the two rack structures 32 are symmetrically arranged on two sides of the vehicle door 2, two gears 31 are correspondingly arranged on the vehicle roof 1, and the gears 31 can be meshed with the corresponding rack structures 32.

Specifically, a guide groove 4 may be provided at a middle position of the two rack structures 32, and the guide groove 4 may be provided in parallel with and spaced apart from the rack structures 32.

Alternatively, the vehicle may comprise a drive 5; the driving member 5 may be provided to the roof 1; the driving member 5 may be disposed corresponding to the gear 31, and the driving member 5 may be configured to drive the corresponding gear 31 along the rack structure 32.

In the embodiment of the utility model, the driving member 5 is disposed corresponding to the gear 31, so that the driving member 5 can provide driving force for the gear 31, and further drive the gear 31 to move along the extending direction of the rack structure 32, so as to realize opening and closing of the vehicle door 2.

Specifically, the driving members 5 and the gears 31 are disposed in one-to-one correspondence, so that one driving member 5 can be used to drive the corresponding one of the gears 31 for movement. Alternatively, when the gear 31 includes two gears, the driving member 5 may be connected to the two gears 31 to simultaneously drive the two gears 31 to move, and the arrangement may be specifically set according to actual requirements, which is not particularly limited in the embodiment of the present utility model.

Further, the driving member 5 may include a first driving member and a second driving member, where the first driving member may be disposed at an end of the roof near the first side door 21, and the first driving member may drive the gear 31 disposed corresponding to the first driving member, so that the gear 31 is engaged with the rack structure 32 on the first side door 21 to drive the first side door 21 to open and close. The second driving member may be disposed at one end of the roof near the second side door 22, and the second driving member may drive the gear 31 disposed corresponding to the second driving member, so that the gear 31 is in meshed connection with the rack structure 32 on the second side door 22 to drive the second side door 22 to open and close.

Specifically, the driving member 5 may be a motor or an air cylinder, etc., and may be specifically set according to actual requirements, which is not specifically limited in the embodiment of the present utility model.

Specifically, the case where the driving member 5 is a motor is exemplified, and other cases can be referred to as the arrangement: the motor rotates positively, and the gear 31 is meshed with the rack structure 32, so that the vehicle door 2 is opened; the motor is reversed and the gear 31 is engaged with the rack structure 32 so that the door 2 is closed.

Optionally, the vehicle may comprise a cockpit; an operation button can be arranged in the cockpit; the operation button may be electrically connected to the driving member 5 through a wire harness, and the operation button is used for adjusting the working state of the driving member 5.

In the embodiment of the utility model, the operation button is arranged in the cockpit and can be electrically connected with the driving piece 5 through the wire harness, so that a driver can conveniently operate the operation button, and further the working state of the driving piece 5 is controlled to adjust the opening and closing of the vehicle door 2.

Specifically, the operation buttons may include a first button and a second button that are independently provided, and the first button may be provided corresponding to the first driving piece to control the opening and closing of the first side door 21 by the first driving piece; the second button may be provided corresponding to the second driving member to control the opening and closing of the second side door 22 by the second driving member.

Alternatively, the door 2 may have an arcuate structure, and the corresponding first surface 11 and second surface are both arcuate surfaces.

In the embodiment of the utility model, the first surface 11 and the second surface are both arc-shaped surfaces, so that the vehicle roof 1 can be in an arc-shaped structure, and the vehicle door 2 is also in an arc-shaped structure, so that the shapes of the vehicle door 2 and the vehicle roof 1 are adapted, and the stacking reliability of the vehicle door 2 and the vehicle roof 1 can be improved.

Specifically, the door 2 has an arc-shaped structure, the rack structure 32 correspondingly provided on the door 2 may be an arc-shaped tooth, and the guide groove 4 correspondingly provided on the door 2 may be an arc-shaped groove.

The vehicle with the sliding door in the embodiment of the utility model at least has the following advantages:

in the embodiment of the utility model, the vehicle roof comprises a first surface and a second surface which are opposite, when both the vehicle doors are in an open state, one of the vehicle doors can be attached to the first surface of the vehicle roof, the other vehicle door can be attached to the second surface of the vehicle roof, and the vehicle roof is clamped between the two vehicle doors, so that under the condition of opening the vehicle doors, the vehicle doors can be positioned at the top of the vehicle and are completely opened, the vehicle doors are prevented from occupying the space of the opening of the vehicle doors, so that the opening of the vehicle doors can have a larger space, and a user can get on or off the vehicle conveniently.

While preferred embodiments of the present utility model have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiment and all such alterations and modifications as fall within the scope of the embodiments of the utility model.

Finally, it is further noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or terminal. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article or terminal device comprising the element.

The foregoing has outlined a detailed description of a vehicle having a sliding door, wherein specific examples are provided herein to illustrate the principles and embodiments of the present utility model, the above examples being provided only to assist in understanding the method and core concepts of the present utility model; meanwhile, as those skilled in the art will have variations in the specific embodiments and application scope in accordance with the ideas of the present utility model, the present description should not be construed as limiting the present utility model in view of the above.

Claims (11)

1. A vehicle having a sliding door, comprising: a vehicle roof (1) and two vehicle doors (2), the vehicle roof (1) comprising opposite first and second surfaces (11, 2); wherein,

one of the vehicle doors (2) is movably connected to a first surface (11) of the vehicle roof (1), and the other vehicle door (2) is movably connected to a second surface of the vehicle roof (1);

the vehicle doors (2) are switched between an open state and a closed state, and when both the vehicle doors (2) are in the closed state, the two vehicle doors (2) are respectively arranged on two opposite sides of the vehicle roof (1); under the condition that two car doors (2) are in the open state, one car door (2) is attached to a first surface (11) of the car roof (1), the other car door (2) is attached to a second surface of the car roof (1), and the car roof (1) is clamped between the two car doors (2).

2. The vehicle according to claim 1, characterized in that a side of the door (2) facing the roof (1) is provided with a rack structure (32), and a side of the roof (1) facing the door (2) is provided with a gear (31);

the rack structure (32) extends in the direction of movement of the vehicle door (2);

the gear (31) is arranged corresponding to the rack structure (32), and the gear (31) is meshed with the corresponding rack structure (32) so as to realize that the vehicle door (2) is movably connected with the vehicle roof (1).

3. The vehicle according to claim 2, characterized in that the rack arrangement (32) is arranged in a middle position of the door (2).

4. A vehicle according to claim 3, characterized in that the side of the door (2) facing the roof (1) is provided with a first guide and the side of the roof (1) facing the door (2) is provided with a second guide;

the first guide piece is in limit fit with the second guide piece, and the first guide piece and the second guide piece are connected in a sliding mode along the moving direction of the vehicle door (2).

5. The vehicle according to claim 4, characterized in that the first guide is a guide slot (4) and the corresponding second guide is a guide post;

the guide groove (4) extends along the moving direction of the vehicle door (2), and the guide post is embedded in the guide groove (4) and is connected with the guide groove (4) in a sliding mode.

6. The vehicle according to claim 5, characterized in that the opposite sides of the rack structure (32) are provided with two guide grooves (4), respectively;

the rack structure (32) is parallel to the guide groove (4) and is arranged at intervals.

7. The vehicle according to claim 4, characterized in that the first guide is a guide post and the corresponding second guide is a guide slot (4);

the guide groove (4) extends along the moving direction of the vehicle door (2), and the guide post is embedded in the guide groove (4) and is connected with the guide groove (4) in a sliding mode.

8. The vehicle according to claim 2, characterized in that the number of rack structures (32) is two;

the two rack structures (32) are symmetrically arranged on two sides of the vehicle door (2).

9. A vehicle according to claim 3 or 8, characterized in that the vehicle comprises a drive (5);

the driving piece (5) is arranged on the vehicle roof (1);

the driving piece (5) is arranged corresponding to the gear (31), and the driving piece (5) is used for driving the corresponding gear (31) to move along the rack structure (32).

10. The vehicle of claim 9, characterized in that the vehicle comprises a cockpit;

an operation button is arranged in the cockpit;

the operation button is electrically connected with the driving piece (5) through a wire harness and is used for adjusting the working state of the driving piece (5).

11. The vehicle according to claim 1, characterized in that the door (2) is of an arcuate configuration, the corresponding first surface (11) and second surface being arcuate.