WO2024131088A1

WO2024131088A1 - Motion system with controllable rotation range

Info

Publication number: WO2024131088A1
Application number: PCT/CN2023/112060
Authority: WO
Inventors: 邓梅梅
Original assignee: 上海灵转动力科技有限公司
Priority date: 2023-08-09
Filing date: 2023-08-09
Publication date: 2024-06-27

Abstract

A motion system with a controllable rotation range, the motion system comprising a base (P), a first component (10), a second component (20) and a third component (30), wherein the first component (10) can rotate relative to the base (P) around a first rotation axis (R1), the second component (20) can rotate relative to the first component (10) around a second rotation axis (R2), and the third component (30) can rotate relative to the second component (20) around a third rotation axis (R3); the included angle between the first rotation axis (R1) and the second rotation axis (R2) is a1, and the included angle between the second rotation axis (R2) and the third rotation axis (R3) is a2, 0° < a1 < 90°, and 0° < a2 < 90°; and the third component (30) comprises a first collision area, the base (P) comprises a second collision area, and the first collision area can interfere with the second collision area, such that a cone angle of a conical area covered by the third rotation axis (R3) during motion is smaller than both 4*a1 and 4*a2. The motion system has high stability and a strong load capacity, and the rotation range thereof can be set as required.

Description

Motion system with controllable rotation range

Technical Field

The present application relates to the field of motion mechanisms, and more specifically to a motion system with a controllable rotation range.

Background technique

A universal joint is a pivot support that allows an object to rotate around an axis. Typically, a universal joint includes a set of three rotating parts, with the first rotating part mounted on a bracket, the second rotating part mounted on the first rotating part, and the third rotating part mounted on the second rotating part, and the rotating parts have orthogonal pivots between each other, allowing the object on the rotating part (i.e., the aforementioned third rotating part) mounted on the terminal of the connecting chain to remain independent of the rotation of the bracket.

19 shows a conventional universal joint having terminal rotation axes X, Y and Z. The rotational freedom of the terminal rotation axes X, Y, Z is realized by three mutually perpendicular rotation joints A, B and C. Such a universal joint is also called an orthogonal universal joint.

Orthogonal universal joints have the following disadvantages:

First, due to the limitation of the arm length of the universal joint (i.e. the distance from the terminal rotation center to the rotation joint), the effective load that the orthogonal universal joint can withstand is limited.

Second, according to the application scenario of the universal joint, some postures of the terminal platform during motion will be affected by the rotating parts during the application process. For example, as shown in Figure 20, when observing along the arrow direction in the figure, the rotating joint B blocks the view of the payload on the terminal platform, for example, when the terminal platform carries application devices such as radar, video camera and camera, this is an undesirable phenomenon.

Patent application PCT/CN2022/082279 (WO2023040229A1) discloses a non-orthogonal universal joint, which includes two rotating parts that can slide relative to each other on a plane with an inclined angle of α, which is equivalent to providing a non-orthogonal universal joint. In addition, US Patent US11346495B2 describes a control system using a non-orthogonal universal joint. Used as a stabilization system for cameras and video equipment. However, in other applications, non-orthogonal gimbals are very rare.

In addition, in practical applications, in some cases, it is necessary to control the working range, or the rotation range, of the non-orthogonal universal joint, and no reasonable and effective solution has been found in the prior art.

Summary of the invention

The purpose of the present application is to overcome or at least alleviate the deficiencies of the above-mentioned prior art and to provide a non-orthogonal universal joint whose rotation range can be controlled.

The present application provides a motion system with a controllable rotation range, the motion system comprising a base, a first component, a second component and a third component.

The first component is rotatably connected to the base, so that the first component can rotate relative to the base around a first rotation axis.

The second component is rotatably connected to the first component, so that the second component can rotate relative to the first component around a second rotation axis.

The third component is rotatably connected to the second component, so that the third component can rotate around a third rotation axis relative to the second component.

The first rotation axis, the second rotation axis and the third rotation axis intersect at point O,

The angle between the first rotating shaft and the second rotating shaft is a1, the angle between the second rotating shaft and the third rotating shaft is a2, 0°＜a1＜90°, 0°＜a2＜90°, wherein,

The third component forms a first collision zone, and the base forms a second collision zone.

During the movement of the third component relative to the base, the first collision zone can interfere with the second collision zone in a contact manner or a non-contact manner, so that the cone angle of the conical area covered by the third rotating shaft during the movement is less than 4*a1 and less than 4*a2.

In at least one embodiment, the first collision area and the second collision area are both annular.

In at least one embodiment, when the third component interferes with the base The first collision area and the second collision area abut against each other.

In at least one embodiment, in the direction where the third rotation axis is located, the first collision area and the second collision area are arranged opposite to each other.

In at least one embodiment, the first collision zone and the second collision zone are arranged to be nested with each other.

In at least one embodiment, the third component is in the shape of a cap.

The third component comprises a third component rib in the shape of a brim, and the first collision zone is located at the edge of the third component rib.

In at least one embodiment, the first component and the second component are assembled together to form a spherical shape, and the third component is partially sleeved outside the second component.

In at least one embodiment, a1=a2=α.

In at least one embodiment, the interference position between the third component and the base is such that the cone angle of the conical area covered by the third rotating shaft during the movement is less than 2α.

In at least one embodiment, in an orthogonal coordinate system, the third component has three rotational degrees of freedom about an X-axis, a Y-axis, and a Z-axis.

In at least one embodiment, in an orthogonal coordinate system, the third component has two rotational degrees of freedom about an X-axis and a Y-axis, and the rotational degree of freedom of the third component relative to a Z-axis is limited.

In at least one embodiment, the third component includes a third component limiting portion, and the base includes a base limiting portion, and the third component limiting portion and the base limiting portion cooperate with each other, so that the third component can rotate around the X-axis and around the Y-axis relative to the base, and the third component cannot rotate around the Z-axis relative to the base.

In at least one embodiment, one of the third component limiting portion and the base limiting portion is a slot and the other is a pin, and the pin passes through the slot.

During the movement of the third member, at least one of the pins is at least partially retained in the In the tank.

In at least one embodiment, there are two pins, and a line connecting the two pins passes through the point O.

In at least one embodiment, the pin is formed on the third component and the slot is formed on the base.

The beneficial effects of this application include:

(i) The motion system according to the present application has a shorter arm than the conventional orthogonal universal joint rotation system, thereby increasing the payload weight and volume capacity, especially in limited volume or operating space. In addition, the rotation range of the terminal platform of the motion system according to the present application is limited, which allows the terminal platform to avoid moving to an undesirable position, for example, thereby preventing the terminal platform from moving to a singular point position and making the motion range of the motion platform symmetrical, and for example, preventing the terminal platform from moving to a position where the load may tip over.

The motion system provided in the present application, for example, a non-orthogonal universal joint can be used for rotation or support purposes, and the uses include but are not limited to pan/tilt heads, chairs, cameras, entertainment equipment, sports or rehabilitation training equipment, household appliances, industrial robots, automobiles and solar tracking systems.

(ii) The motion system according to the present application can also limit the rotation of the terminal platform in a certain direction as required, so as to facilitate its use in certain special application scenarios.

BRIEF DESCRIPTION OF THE DRAWINGS

1 to 3 are schematic structural diagrams of three possible non-orthogonal universal joints according to the present application.

FIG. 4 is a schematic diagram of the motion range of the payload when the non-orthogonal universal joint of FIG. 1 is carrying the payload.

FIG. 5 is a schematic diagram of a motion system with controllable rotation range according to a first embodiment of the present application.

6 and 7 are cross-sectional views of FIG. 5 at two different positions.

FIG. 8 is a schematic diagram of the structural decomposition of FIG. 5 .

FIG. 9 is a schematic structural diagram of the base in FIG. 5 .

FIG. 10 is a schematic structural diagram of the first component in FIG. 5 .

FIG. 11 is a schematic structural diagram of the second component in FIG. 5 .

FIG. 12 is a schematic structural diagram of the third component in FIG. 5 .

FIG. 13 is a schematic diagram showing the connection relationship of the main components of the motion system with controllable rotation range according to the first embodiment of the present application.

FIG. 14 is a schematic diagram of a motion system with controllable rotation range according to a second embodiment of the present application.

FIG. 15 is a partially exploded schematic diagram of FIG. 14 .

FIG. 16 is a schematic structural diagram of the base in FIG. 14 .

FIG. 17 is a cross-sectional view of FIG. 14 .

FIG. 18 is a schematic diagram showing the connection relationship of the main components of the motion system with controllable rotation range according to the second embodiment of the present application.

FIG. 19 is a schematic diagram of an orthogonal universal joint in the prior art.

FIG. 20 is a schematic diagram of an orthogonal universal joint in the prior art during motion.

Description of reference numerals:

P base; P1 base matching part; P2 base limiting part;

10 first component; 11 first matching portion of the first component; 12 second matching portion of the first component;

20 second component; 21 first matching portion of the second component; 22 second matching portion of the second component;

30 third component; 31 first matching portion of the third component; 301 third component retaining edge; 32 third component limiting portion;

B1 first bearing assembly; B10 first bearing; B11 first retaining ring of first bearing assembly; B12 second retaining ring of first bearing assembly;

B2 second bearing assembly; B20 second bearing; B21 first retaining ring of second bearing assembly; B22 second retaining ring of second bearing assembly;

B3 third bearing assembly; B30 third bearing; B31 third bearing first retaining ring; B32 third bearing second retaining ring;

R1 is the first rotating axis; R2 is the second rotating axis; R3 is the third rotating axis.

Detailed ways

The exemplary embodiments of the present application are described below with reference to the accompanying drawings. It should be understood that these specific descriptions are only used to teach those skilled in the art how to implement the present application, and are not intended to exhaust all possible methods of the present application, nor to limit the scope of the present application.

Unless otherwise specified, the present application describes the positional relationship of each component using the three-dimensional coordinate system shown in Figure 1. It should be understood that the positional relationship defined by the X, Y and Z axes in the present application is relative, and the coordinate axes can be rotated in space according to the actual application of the device.

FIG1 shows a model of a non-orthogonal universal joint (hereinafter also referred to as a motion system). The universal joint includes a first component 10, a second component 20 and a third component 30, wherein the third component 30 is a terminal platform, and the third component 30 has rotational freedom around the X-axis, the Y-axis and the Z-axis in an orthogonal coordinate system. Among them, the rotation axis of the first component 10 relative to the base (not shown in the figure) is the rotation axis A, the rotation axis of the second component 20 relative to the first component 10 is the rotation axis B, and the rotation axis of the third component 30 relative to the second component 20 is the rotation axis C. The angle between the rotation axis A and the rotation axis B is α, and the angle between the rotation axis B and the rotation axis C is also α, 0°<α<90°. In the position in the figure, the rotation axis C is parallel to the Z axis.

The first component 10 and the second component 20 act as arms of a non-orthogonal universal joint, and the combination of their rotational motions provides the third component 30 with rotations around the X-axis and the Y-axis. During the rotation of the first component 10 and the second component 20 around the rotation axis A and the rotation axis B, respectively, the rotation angle of the third component 30 around the X-axis and the Y-axis will not exceed 4 times the angle α, or in other words, the rotation area of the third component 30 around the X-axis will not exceed ±2α, and the rotation area of the third component 30 around the Y-axis will not exceed ±2α.

4 , taking the rotation axis of the third component 30 as the target object, within the rotation range of the third component 30 , the area covered by the rotation axis of the third component 30 during the rotation process forms a cone angle, and half of the cone angle is 2α.

The arm of the non-orthogonal gimbal can be located on one side of the terminal platform, and the arm length of the non-orthogonal gimbal is shorter than that of the orthogonal gimbal. The shorter gimbal arm can carry a higher payload weight, or the non-orthogonal gimbal has a higher payload weight to volume ratio.

High positional accuracy and payload weight-to-volume ratio make non-orthogonal gimbals more popular in certain applications, such as but not limited to pan/tilts, chairs, cameras, entertainment equipment, sports or rehabilitation training equipment, home appliances, industrial robots, automobiles, and solar tracking systems.

In addition to being realized by using a combination of rotating parts in the form of arms and joints, the above-mentioned non-orthogonal universal joint can also be realized by a combination of rotating parts in the form of rotating tables stacked in sequence. The present application does not limit the specific form of the rotating parts. For example, Figures 2 and 3 show two other non-orthogonal universal joints. Among them, the universal joint shown in Figure 2 is essentially the same as the universal joint shown in Figure 1.

It is worth noting that the intersection of the rotation axes of the two rotating parts (the first part 10 and the second part 20) defines a virtual origin O, and the payload will rotate around the virtual origin O. By adjusting the shape and size of the rotating parts, the position of the virtual origin O can be adjusted, thereby changing the rotation trajectory of the terminal platform (the third part 30), for example, the motion trajectories of the third part 30 in Figures 2 and 3 are different.

Next, in conjunction with FIG. 4 to FIG. 19 , motion systems according to two embodiments of the present application are introduced.

First embodiment

4 to 13 , the motion system according to the first embodiment of the present application is a non-orthogonal universal joint with a controllable rotation range of a terminal platform.

The motion system in this embodiment includes a base P, a first component 10 , a second component 20 and a third component 30 .

The first component 10 is mounted on the base P, and the base matching portion P1 matches with the first component first matching portion 11 , so that the first component 10 can rotate relative to the base P around the first rotation axis R1 .

The second component 20 is installed on the first component 10, and the second matching portion 12 of the first component is connected to the first The mating portions 21 are mated with each other so that the second component 20 can rotate relative to the first component 10 around the second rotation axis R2.

The third component 30 is mounted on the second component 20 , and the second matching portion 22 of the second component cooperates with the first matching portion 31 of the third component, so that the third component 30 can rotate relative to the second component 20 around the third rotation axis R3 .

Fig. 13 is a schematic diagram showing the positional relationship between the base P, the first component 10, the second component 20 and the third component 30. The positional matching relationship between the matching parts of these components makes the first rotation axis R1, the second rotation axis R2 and the third rotation axis R3 intersect each other at point O.

The angle between the first rotation axis R1 and the second rotation axis R2 is a1, and the angle between the second rotation axis R2 and the third rotation axis R3 is a2. 0°<a1<90°, 0°<a2<90°. In this embodiment, a1=a2=α. It should be understood that since the perspective in FIG. 13 is a two-dimensional perspective of a cross-section, and the angles a1 and a2 shown in the figure are angles in three-dimensional space, the angle size ratio shown on paper cannot represent the actual angle size ratio in space.

The above position and connection relationship enable the third component 30 to have three rotational degrees of freedom in an orthogonal coordinate system around the point O which is a virtual rotation center.

Specifically, in this embodiment, the base P is substantially annular, the first component 10 and the second component 20 are asymmetric hemispherical, and the third component 30 is hemispherical shell or cap-shaped.

An inclined base fitting portion P1 is formed on one side of the annular body of the base P, and the base fitting portion P1 is truncated. The spherical area of the hemispherical body of the first component 10 is partially recessed inward to form the first fitting portion 11 of the first component. A first bearing assembly B1 is provided between the base fitting portion P1 and the first fitting portion 11 of the first component. The first bearing assembly B1 includes a first bearing B10 and a first bearing assembly first retaining ring B11 and a first bearing assembly second retaining ring B12 located at both ends of the first bearing B10 and connected to the outer ring and the inner ring of the bearing in a torsion-resistant manner (non-rotatably connected relative to each other).

When the first component 10 is mounted on the base P, optionally, the first component 10 is partially recessed into the annular space formed by the annular body of the base P, so that the first component 10 and the base P as a whole occupy a smaller space in the Z direction.

The plane side of the hemispherical body of the first component 10 forms the first component second matching portion 12, and the plane side of the hemispherical body of the second component 20 forms the second component first matching portion 21. The first component second matching portion 12 and the second component first matching portion 21 are arranged opposite to each other, and a second bearing assembly B2 is arranged therebetween. The second bearing assembly B2 includes a second bearing B20 and a second bearing assembly first retaining ring B21 and a second bearing assembly second retaining ring B22 located at both ends of the second bearing B20 and respectively connected to the inner ring and the outer ring of the bearing in a torsion-resistant manner.

The spherical area of the hemispherical main body of the second component 20 also partially protrudes to form the second component second matching portion 22. The top of the inner cavity of the spherical shell structure of the third component 30 is formed with the third component first matching portion 31. The second component second matching portion 22 and the third component first matching portion 31 are arranged opposite to each other, and a third bearing assembly B3 is arranged between the two. The third bearing assembly B3 includes a third bearing B30 and a third bearing assembly first retaining ring B31 and a third bearing assembly second retaining ring B32 located at both ends of the third bearing B30 and connected to the outer ring and the inner ring of the bearing respectively to prevent torsion.

Next, it is introduced how the terminal platform, that is, the third component 30 in the motion system according to the present application can rotate within a controlled range.

In this embodiment, the third component 30 includes an annular, brim-shaped third component rib 301, which extends toward the base P, so that during the rotation of the third component 30, the third component rib 301 will touch the base P in an area with a larger rotation range, or interfere with the base P, or be blocked by the base P and cannot further expand the rotation range.

By limiting the rotation range of the third component 30 through the contact interference between the base P and the third component 30, the third component 30 can be prevented from rotating to an undesired position. For example, in some cases, in order to prevent the third component 30 from encountering a singularity (also called a singularity) within the rotation range, the direction of the entire motion system can be changed so that the singularity is located at the theoretical maximum operating angle of the motion system. In this case, the working range of the system is asymmetric. By limiting the rotation range of the third component 30, the working range of the system can be adjusted to a reasonable and symmetrical range again. In this application, the interference area is optionally set so that half of the cone angle of the conical area covered by the third rotation axis R3 during the movement is less than α.

The areas where the third component 30 and the base P may interfere are respectively referred to as the first collision zone and the second collision zone. In this embodiment, the first collision zone is located at the edge of the third component rib 301, and the second collision zone is located at the outer peripheral wall of the base P.

It should be understood that, although in the present embodiment, the first collision zone and the second collision zone are arranged relative to each other in the extension direction of the third rotation axis R, this is not the only arrangement of the first collision zone and the second collision zone. For example, in other possible arrangements, the first collision zone and the second collision zone may also be arranged to be nested with each other.

In addition to the physical collision and contact interference as in the present embodiment, the first collision zone and the second collision zone can also be set as non-contact interference with controllable distance. For example, in an active system, or a system with a power source for controlling the rotation of the first component 10, the second component 20 and the third component 30, a distance sensor can be used to identify the interval distance between the first collision zone and the second collision zone. When the interval distance is less than or equal to a certain set value, the system triggers the non-contact interference mechanism to stop the third component 30 from further expanding the rotation range.

Second embodiment

14 to 18 , the second embodiment of the present application is introduced. The second embodiment is a variation of the first embodiment, and components with the same or similar structures or functions as those in the first embodiment are marked with the same reference numerals, and detailed descriptions of these components are omitted.

The main difference between this embodiment and the first embodiment is that the third component 30 has only two degrees of rotational freedom relative to the base P, for example, the third component 30 can only perform tilt and roll movements but cannot swing left and right.

The base P includes a pair of base limiting portions P2. The base limiting portions P2 are fork-shaped and surround the outer circumference of the third component 30. Each base limiting portion P2 defines a groove.

The third component 30 includes a pair of third component stopper portions 32, and the third component stopper portions 32 are pin-shaped. A line connecting the two third component stopper portions 32 passes through point O.

Each third component stopper 32 can extend into a groove defined by a base stopper P2, and during the movement of the third component 30, at least one third component stopper 32 is at least partially accommodated in the groove. Inside.

The groove of the base stopper P2 allows the third component stopper 32 to slide only in the extending direction of the groove, that is, the third component 30 can tilt, or the third component stopper 32 can rotate around its own axis, that is, the third component 30 can pitch. The width of the groove prevents the third component stopper 32 from moving left and right in the groove, that is, the third component 30 cannot rotate around the Z axis relative to the base P.

In this embodiment, the fork-shaped base limiting portion P2 makes one end of the slot open, which makes it easier to install the third component limiting portion 32 and the slot.

It should be understood that although the paired third component limiting portions 32 and the paired base limiting portions P2 can enhance the stability of limiting the third component 30, this is not necessary, and there can be only one third component limiting portion 32 and one base limiting portion P2.

It should be understood that in other possible implementations, the base limiting portion P2 may be configured to be pin-shaped, while the third component limiting portion 32 may be configured to be groove-shaped.

It should be understood that, in other possible embodiments, the base limit portion P2 can be detachably arranged with the main body of the base P, and/or the third component limit portion 32 can be detachably arranged with the main body of the third component 30, and the base limit portion P2 and/or the third component limit portion 32 are only installed in place in applications where the third component 30 needs to be rotationally limited; in other applications, the possibility of retaining three degrees of rotational freedom is reserved for the third component 30.

It should be understood that the above-mentioned embodiments and some aspects or features thereof may be appropriately combined.

It should be understood that the above embodiments are merely exemplary and are not intended to limit the present application. Those skilled in the art may make various modifications and changes to the above embodiments under the guidance of the present application without departing from the scope of the present application. For example, the rotating parts (first part, second part and third part) of the motion system according to the present application may be stacked rotating tables as shown in the first embodiment and the second embodiment, or may be rotating arms connected by joints as shown in FIG1.

Claims

A motion system with a controllable rotation range, the motion system comprising a base (P), a first component (10), a second component (20) and a third component (30),

The first component (10) is rotatably connected to the base (P), so that the first component (10) can rotate relative to the base (P) around a first rotation axis (R1),

The second component (20) is rotatably connected to the first component (10), so that the second component (20) can rotate relative to the first component (10) around a second rotation axis (R2),

The third component (30) is rotatably connected to the second component (20), so that the third component (30) can rotate relative to the second component (20) around a third rotation axis (R3),

The first rotation axis (R1), the second rotation axis (R2) and the third rotation axis (R3) intersect at point O,

The angle between the first rotating shaft (R1) and the second rotating shaft (R2) is a1, the angle between the second rotating shaft (R2) and the third rotating shaft (R3) is a2, 0°＜a1＜90°, 0°＜a2＜90°, characterized in that:

The third component (30) is formed with a first collision zone, and the base (P) is formed with a second collision zone,

During the movement of the third component (30) relative to the base (P), the first collision zone can interfere with the second collision zone in a contacting manner or a non-contacting manner, so that the cone angle of the conical area covered by the third rotating shaft (R3) during the movement is less than 4*a1 and less than 4*a2.
The motion system with controllable rotation range according to claim 1, characterized in that the first collision area and the second collision area are both annular.
The motion system with controllable rotation range according to claim 1, characterized in that:

When the third component (30) interferes with the base (P), the first collision area and the second collision area abut against each other.
The motion system with controllable rotation range according to claim 3 is characterized in that, in the direction where the third rotation axis (R3) is located, the first collision area and the second collision area are arranged opposite to each other.
The motion system with controllable rotation range according to claim 3, characterized in that the first collision area and the second collision area are arranged to be nested with each other.
The motion system with controllable rotation range according to claim 4, characterized in that the third component (30) is in the shape of a cap.

The third component (30) comprises a third component rib (301) in the shape of a hat brim, and the first collision zone is located at the edge of the third component rib (301).
The motion system with controllable rotation range according to claim 6 is characterized in that the first component (10) and the second component (20) are assembled together to form a sphere, and the third component (30) is partially sleeved on the outside of the second component (20).
The motion system with controllable rotation range according to claim 1 is characterized in that a1=a2=α.
The motion system with controllable rotation range according to claim 8 is characterized in that the interference position between the third component (30) and the base (P) makes the cone angle of the conical area covered by the third rotating shaft (R3) during the movement less than 2α.
The motion system with controllable rotation range according to any one of claims 1 to 9, characterized in that, in an orthogonal coordinate system, the third component (30) has three rotational degrees of freedom around the X-axis, the Y-axis and the Z-axis.
The motion system with controllable rotation range according to any one of claims 1 to 9 is characterized in that, in an orthogonal coordinate system, the third component (30) has two rotational degrees of freedom around an X-axis and a Y-axis, and the rotational degree of freedom of the third component (30) relative to a Z-axis is limited.
The motion system with controllable rotation range according to claim 11, characterized in that The third component (30) includes a third component limiting portion (32), and the base (P) includes a base limiting portion (P2). The third component limiting portion (32) cooperates with the base limiting portion (P2) so that the third component (30) can rotate around the X-axis and around the Y-axis relative to the base (P), and the third component (30) cannot rotate around the Z-axis relative to the base (P).
The motion system with controllable rotation range according to claim 12, characterized in that one of the third component limiting portion (32) and the base limiting portion (P2) is a groove and the other is a pin, and the pin passes through the groove.

During movement of the third member, at least one of the pins is at least partially retained in the slot.
The motion system with controllable rotation range according to claim 13 is characterized in that there are two pins, and the line connecting the two pins passes through the point O.
The motion system with controllable rotation range according to claim 13, characterized in that the pin is formed on the third component (30) and the groove is formed on the base (P).