CN218765328U

CN218765328U - Inertia measuring unit

Info

Publication number: CN218765328U
Application number: CN202223252202.4U
Authority: CN
Inventors: 吴雾; 黄立成; 黄晓群
Original assignee: Guangzhou Asensing Technology Co Ltd
Current assignee: Guangzhou Asensing Technology Co Ltd
Priority date: 2022-12-02
Filing date: 2022-12-02
Publication date: 2023-03-28
Anticipated expiration: 2032-12-02
Also published as: WO2024114196A1

Abstract

An embodiment of the utility model provides an inertia measurement unit relates to inertia measurement technical field. This inertia measurement unit includes the box body, the lid, circuit board and buffer block, the lid fits the box body, the installation cavity is injectd jointly to lid and box body, the integration has inertia measurement unit chip on the circuit board, the circuit board sets up in the installation cavity, the buffer block is installed in the circuit board, and buffer block butt lid and box body simultaneously, because the lid closes under the condition of box body, buffer block butt lid and box body simultaneously, utilize the pressure between lid and the box body to compress tightly fixed circuit board. Because need not the fix with screw, consequently just there is not locking stress, and the buffer block can also keep apart the locking stress that produces when the screw locking box body lid, avoids or reduces the stress of transmitting the inertia measurement unit chip on the circuit board, has reduced the influence that the long-time accumulative effect of stress was calculated to IMU's gesture, improves the positioning accuracy.

Description

Inertia measuring unit

Technical Field

The utility model relates to an inertia measurement technical field particularly, relates to an inertia measurement unit.

Background

An Inertial Measurement Unit (IMU) measures angular velocity and acceleration of an object in a three-dimensional space by combining a three-axis gyroscope and a three-axis accelerometer, and calculates the attitude of the object according to the angular velocity and the acceleration. In long-term application practice, it is found that the measurement result of the inertial measurement unit often generates deviations of different degrees from the initial state, some deviations accumulate more and more along with time, the attitude calculation of the IMU is seriously influenced, and finally the positioning accuracy is lost. Therefore, the problem to be solved in the art is to solve the deviation of the measurement result of the inertial measurement unit and to improve the measurement accuracy.

SUMMERY OF THE UTILITY MODEL

The utility model provides an inertia measurement unit, its long-time cumulative effect that can reduce stress improves the location accuracy to the influence of IMU's gesture reckoning.

The embodiment of the utility model discloses a can realize like this:

an embodiment of the utility model provides an inertia measurement unit, it includes:

a box body;

the cover body covers the box body, and an installation cavity is defined by the cover body and the box body together;

the circuit board is integrated with an inertia measurement unit chip and arranged in the installation cavity; and

the buffer block is arranged on the circuit board and is simultaneously abutted to the cover body and the box body.

Optionally, the buffer block is clamped to the edge of the circuit board.

Optionally, the circuit board is a polygonal board body, the circuit board has a plurality of corner portions, the number of the buffer blocks is multiple, and one buffer block is mounted on each corner portion.

Optionally, the circuit board is a rectangular board body, the circuit board has four corner portions, the number of the buffer blocks is four, and the four buffer blocks are respectively mounted on the four corner portions.

Optionally, the buffer block is provided with a clamping groove, and the corner portion is matched with the clamping groove in a clamping mode.

Optionally, the corner portion is recessed toward a middle portion of the circuit board to form a notch, and the snap groove is fitted to the notch.

Optionally, the clamping groove is an L-shaped groove, a U-shaped groove or an arc-shaped groove.

Optionally, the buffer block has a first side wall and a second side wall which are away from the clamping groove, the first side wall and the second side wall are distributed in an included angle, the circuit board has a first wall surface and a second wall surface, and the first wall surface and the second wall surface are located on two sides of the notch;

wherein the first sidewall and the second sidewall are coplanar with the first wall and the first wall, respectively.

Optionally, the length of the buffer block in the thickness direction of the circuit board is greater than the thickness of the circuit board.

Optionally, the box body includes a first housing and a first boss, the first boss is connected with the first housing, the cover covers the first housing, the cover and the first housing together define the installation cavity, the first boss is located in the installation cavity, and the buffer block abuts between the first boss and the cover.

Optionally, the cover body includes a second housing and a second boss, the second boss is connected to the second housing, the second housing covers the first housing, the second housing and the first housing define the installation cavity together, the second boss is located in the installation cavity, and the buffer block abuts between the first boss and the second boss.

Optionally, the first boss and the first housing are integrally formed, and the second boss and the second housing are integrally formed.

Optionally, a first fastener is arranged on the first housing, a screw fitting hole is arranged on the second housing, and the screw fitting hole is matched with the first fastener to fixedly connect the first housing with the second housing.

Optionally, the first housing and the second housing are snap-fitted.

Optionally, the inertia measurement unit further includes a circuit board body and a processor, the circuit board body is installed in the box body, and the processor is installed on the circuit board body;

the circuit board body is arranged on one side, far away from the cover body, of the circuit board.

Optionally, the inertia measurement unit further includes a first board-to-board connector and a second board-to-board connector, the first board-to-board connector is mounted on the circuit board, the second board-to-board connector is mounted on the circuit board body, and the first board-to-board connector and the second board-to-board connector are electrically connected.

Optionally, the inertial measurement unit further includes an external data connector, and the external data connector is mounted on the circuit board body.

Optionally, the circuit board and the circuit board body are electrically connected by a flexible circuit board or a cable.

Optionally, the inertia measurement unit further comprises a circuit board body and a second fastener, four through holes are formed in the circuit board body, and the second fastener penetrates through the through holes to fix the circuit board body in the first shell.

Optionally, the number of the first bosses is plural, and the circuit board body is located between the plural first bosses.

Optionally, the buffer block is made of a rubber material.

The utility model discloses inertial measurement unit's beneficial effect includes, for example:

the embodiment of the utility model provides an inertia measurement unit, it includes the box body, the lid, circuit board and buffer block, the lid fits the box body, lid and box body inject the installation cavity jointly, the integration has the inertia measurement unit chip on the circuit board, the circuit board sets up in the installation cavity, the buffer block is installed in the circuit board, and buffer block butt lid and box body simultaneously, because the lid closes under the condition of box body, butt lid and box body are simultaneously pressed to the buffer block, utilize the pressure between lid and the box body to compress tightly fixed circuit board. The influence of the stress generated by screw locking in the process of fixing the circuit board by using the screws is avoided by the fixing mode, the locking stress is not generated due to no screw fixation, the locking stress generated when the box body and the box cover are locked by the screws can be isolated by the buffer block, the stress of an inertia measurement unit chip transmitted to the circuit board is avoided or reduced, the influence of long-time accumulation of the stress on attitude calculation of the IMU is reduced, and the positioning accuracy is improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Fig. 1 is a schematic view of an inertial measurement unit provided in an embodiment of the present invention;

fig. 2 is an exploded view of an inertial measurement unit provided in an embodiment of the present invention;

fig. 3 is a first schematic view of a partial structure of an inertial measurement unit provided in an embodiment of the present invention;

fig. 4 is a second schematic view of a partial structure of an inertial measurement unit provided in an embodiment of the present invention;

fig. 5 is a schematic view of a cover body provided in an embodiment of the present invention.

Icon: 1000-an inertial measurement unit; 100-a cartridge; 110-a first housing; 120-a first boss; 200-a cover body; 210-a second housing; 220-a second boss; 300-a circuit board; 310-corner segments; 311-notch; 312 — a first wall; 313-a second wall; 400-a buffer block; 401-a snap-in groove; 410-a first sidewall; 420-a second side wall; 500-an inertial measurement unit chip; 600-a circuit board body; 700-a processor; 800-external data connector; 10-a first fastener; 20-a second fastener; 30-a first board-to-board connector; 40-second board-to-board connectors.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined or explained in subsequent figures.

In the description of the present invention, it should be noted that, if the terms "upper", "lower", "inner", "outer", etc. indicate the position or positional relationship based on the position or positional relationship shown in the drawings, or the position or positional relationship which is usually placed when the products of the present invention are used, the description is only for convenience of description and simplification, but the indication or suggestion that the indicated device or element must have a specific position, be constructed and operated in a specific orientation, and thus, should not be interpreted as a limitation of the present invention.

Furthermore, the appearances of the terms "first," "second," and the like, if any, are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

It should be noted that the features of the embodiments of the present invention may be combined with each other without conflict.

As described in the background of the present application, the measurement result of the inertial measurement unit often generates deviations of different degrees from the initial state, and some deviations accumulate more and more with time, which seriously affects the attitude calculation of the IMU, and finally causes the positioning accuracy to be lost.

In order to solve the problems in the prior art, after continuous analysis and research, the inventor of the present application finds that stress generated by the inertial measurement unit during assembly, assembly and fixation is transmitted to the inertial measurement unit chip, which causes stress accumulation, and is one of the reasons for influencing the deviation of the measurement result of the inertial measurement unit.

Specifically, in an assembly and assembly mode of an existing inertial measurement unit, a circuit board integrated with an inertial measurement unit chip is usually fixed to a box body of the inertial measurement unit by screws, stress generated when fixing screws are locked is transmitted to the inertial measurement unit chip through the circuit board, influences are exerted on the inertial measurement unit chip, attitude calculation of an IMU is seriously influenced after time accumulation, and finally positioning accuracy is lost.

In view of the above, referring to fig. 1-5, an inertial measurement unit 1000 according to an embodiment of the present invention can solve this problem, which will be described in detail below.

The embodiment of the utility model provides an inertia measurement unit 1000 includes box body 100, lid 200, circuit board 300 and buffer block 400, and wherein, lid 200 covers box body 100, and lid 200 and box body 100 inject the installation cavity jointly.

Wherein, the inertia measurement unit chip 500, i.e. the IMU chip, is integrated on the circuit board 300, the circuit board 300 is disposed in the mounting chamber, the buffer block 400 is mounted on the circuit board 300, and the buffer block 400 abuts against the cover 200 and the box 100 at the same time.

Since the cover 200 is closed to the case 100, the buffer block 400 abuts both the cover 200 and the case 100, and the circuit board 300 is pressed and fixed by the pressure between the cover 200 and the case 100.

This fixed mode has avoided the influence of the produced stress of screw locking among the fix with screw process for circuit board 300, owing to need not the fix with screw, consequently just does not have locking stress, and buffer block 400 can also keep apart the locking stress that produces when screw locking box body 100 and lid 200, avoids or reduces the stress of transmitting the inertia measurement unit chip 500 on circuit board 300, has reduced the influence that the long-time cumulative effect of stress was calculated to IMU's gesture, improves the positioning accuracy.

Certainly, the inertia measurement Unit 1000 further includes a Circuit Board body 600, a processor 700, and an external data connector 800, where the external data connector 800 is an input/output connector, the Circuit Board body 600 is installed in the box body 100, the processor 700 is installed in the Circuit Board body 600, and the external data connector 800 is installed in the Circuit Board body 600, it should be noted that, in this embodiment, both the Circuit Board 300 and the Circuit Board body 600 may be a PCBA (Printed Circuit Board) Board, that is, a Printed Circuit Board, and the processor 700 is an MCU (Microcontroller Unit) processor, that is, a micro control Unit.

The circuit board body 600 is disposed on a side of the circuit board 300 away from the cover, that is, the circuit board body 600 is located on a lower side of the circuit board 300, and the circuit board body 600 and the circuit board 300 are disposed at an interval.

It should be noted that, in order to facilitate that the circuit board 300 and the circuit board body 600 may be disposed at an interval and avoid that the circuit board 300 presses the components integrated on the circuit board body 600, in this embodiment, the box 100 includes the first housing 110 and the four first bosses 120, and the four first bosses 120 are connected to the first housing 110, specifically, the four first bosses 120 are located on an inner wall of the first housing 110 and are distributed at intervals, and the four first bosses 120 may be integrally formed with the first housing 110.

The cover body 200 includes a second housing 210 and four second bosses 220, the second housing 210 covers the first housing 110, the second housing 210 and the first housing 110 jointly define an installation cavity, the four first bosses 120 and the four second bosses 220 are located in the installation cavity, the four second bosses 220 are connected to the second housing 210, specifically, the four second bosses 220 are located on an inner wall of the second housing 210 and are distributed at intervals, and the four second bosses 220 can be integrally formed with the second housing 210.

The four buffer blocks 400 abut against the four first bosses 120 and the four second bosses 220, at this time, the circuit board 300 is simultaneously spaced from the first bosses 120 and the second bosses 220, when the second housing 210 is covered on the first housing 110, the first fastener 10 is screwed down to fixedly connect the first housing 110 and the second housing 210, and at this time, the four first bosses 120 and the four second bosses 220 abut against the four buffer blocks 400 simultaneously to fix the circuit board 300.

It should be noted that, in this embodiment, four first fastening members 10 are disposed on the first casing 110 of the box 100, the first fastening members 10 may be screws, and four screw fitting holes are disposed on the second casing 210, and the screw fitting holes are fitted with the first fastening members 10 to fixedly connect the first casing 110 and the second casing 210, but in other embodiments, the second casing 210 may also be clamped with the first casing 110 through a fastening structure.

The inertia measurement unit 1000 further includes four second fasteners 20, four through holes are formed in the circuit board body 600, the second fasteners 20 are screws, the four second fasteners 20 respectively penetrate through the four through holes to fix the circuit board body 600 in the first casing 110, the circuit board body 600 is located between the four first bosses 120, and the circuit board body 600 is installed in the first casing 110.

In order to facilitate data transmission between the circuit board 300 and the circuit board body 600, the inertial measurement unit 1000 further includes a first board-to-board connector 30 and a second board-to-board connector 40, the first board-to-board connector 30 is mounted on the circuit board 300, the second board-to-board connector 40 is mounted on the circuit board body 600, and the first board-to-board connector 30 and the second board-to-board connector 40 are electrically connected.

Of course, in other embodiments, the inertia measurement unit 1000 may also include a flexible circuit board, which is electrically connected to the circuit board 300 and the circuit board body 600 at the same time, and replaces the first board-to-board connector 30 and the second board-to-board connector 40 with the flexible circuit board.

Alternatively, the inertial measurement unit 1000 may also include a cable, and the cable is used to replace the first board-to-board connector 30 and the second board-to-board connector 40, and is electrically connected to the circuit board 300 and the circuit board body 600 at the same time, so as to implement data transmission between the circuit board 300 and the circuit board body 600.

Specifically, in order to facilitate the installation of the buffer block 400, the buffer block 400 is clamped to the edge of the circuit board 300, and the buffer block 400 may be a flexible member, for example, made of an elastic material such as rubber, so as to isolate the transmission of stress.

It should be noted that the circuit board 300 is a polygonal plate, that is, the circuit board 300 is shaped as a polygonal plate structure, the circuit board 300 has a plurality of corner portions 310, the number of the buffer blocks 400 is plural, one buffer block 400 is mounted on each corner portion 310, and here, the corner portions 310 can be understood as a plurality of corners on the polygonal plate.

For example, in the present embodiment, the circuit board 300 is a rectangular plate body, the circuit board 300 has four corner portions 310, i.e., four right-angled corners, the number of the buffer blocks 400 is four, and the four buffer blocks 400 are respectively mounted at the four corner portions 310.

It should be noted that the length of the buffer block 400 in the thickness direction of the circuit board 300 is greater than the thickness of the circuit board 300, and at this time, the circuit board 300 may be in a spaced state from both the first casing 110 and the second casing 210, so that the stress is completely blocked by the four buffer blocks 400.

Here, the thickness of the circuit board 300 may be understood as a length dimension in the direction of the axis of the first fastener 10.

In addition, this buffer block 400 is equipped with joint groove 401, and joint groove 401 is L shape recess, and corner portion 310 and joint groove 401 joint cooperation to the installation or the dismantlement of buffer block 400 are convenient for.

Of course, in other embodiments, the clamping groove 401 may also be a U-shaped groove or an arc-shaped groove, and may be specifically adjusted according to the shape of the corner portion 310, which is not described herein again.

In order to reduce the volume of the entire inertial measurement unit 1000, the corner portion 310 is recessed toward the middle of the circuit board 300 to form a notch 311, and the snap-in groove 401 is fitted to the notch 311, so that the four buffer blocks 400 can be closer to the middle of the circuit board 300, the requirement on the space volume of the installation chamber is reduced, and the volume of the entire inertial measurement unit 1000 can be reduced.

Of course, in other embodiments, in order to further reduce the volume of the entire inertial measurement unit 1000, the depth of the notch 311 may be deeper, i.e., the buffer block 400 may be closer to the middle of the circuit board 300.

The buffer block 400 has a first sidewall 410 and a second sidewall 420 that are away from the fastening groove 401, the first sidewall 410 and the second sidewall 420 are distributed at an included angle, in this embodiment, the included angle is a right angle, the circuit board 300 has a first wall 312 and a second wall 313, the first wall 312 and the second wall 313 are located on two sides of the notch 311, the first wall 312 and the second wall 313 can be understood as sidewalls of the circuit board 300 in the thickness direction, the first wall 312 and the second wall 313 are also distributed at a right angle, and the first sidewall 410 and the second sidewall 420 are coplanar with the first wall 312 and the first wall 312, respectively, so that the volume of the whole inertia measurement unit 1000 can be further reduced.

To sum up, this inertia measurement unit 1000 includes box body 100, lid 200, circuit board 300 and buffer block 400, and lid 200 covers box body 100, and lid 200 and box body 100 inject the installation cavity jointly, and integrated inertia measurement unit chip 500 on circuit board 300, circuit board 300 set up in the installation cavity, and buffer block 400 is installed in circuit board 300, and buffer block 400 butt lid 200 and box body 100 simultaneously.

Since the cover 200 is closed to the case 100, the buffer block 400 abuts both the cover 200 and the case 100, and the circuit board 300 is pressed and fixed by the pressure between the cover 200 and the case 100. This fixed mode has avoided the influence of the produced stress of screw locking among the fix with screw process of circuit board 300, owing to need not the fix with screw, consequently just does not have locking stress, and buffer block 400 can also keep apart the locking stress that produces when screw locking box body 100 and lid 200, avoids or reduces the stress of transmitting the inertia measurement unit chip 500 on circuit board 300, has reduced the influence that the long-time accumulative effect of stress was calculated to IMU's gesture, improves the location accuracy.

And because the corner part 310 is recessed towards the middle of the circuit board 300 to form a notch 311, the clamping groove 401 is matched with the notch 311, and further, the four buffer blocks 400 can be closer to the middle of the circuit board 300, the requirement on the space volume of an installation chamber is reduced, and the volume of the whole inertia measurement unit 1000 can be reduced.

The above description is only for the specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. An inertial measurement unit, comprising:

a case (100);

the cover body (200), the cover body (200) is covered on the box body (100), and the cover body (200) and the box body (100) jointly define a mounting cavity;

a circuit board (300), an inertial measurement unit chip (500) integrated on the circuit board (300), the circuit board (300) disposed within the mounting chamber; and

a buffer block (400), wherein the buffer block (400) is installed on the circuit board (300), and the buffer block (400) is simultaneously abutted against the cover body (200) and the box body (100).

2. Inertial measurement unit according to claim 1, characterized in that the buffer block (400) is snapped onto the edge of the circuit board (300).

3. The inertial measurement unit according to claim 1, characterized in that the circuit board (300) is a polygonal plate body, the circuit board (300) has a plurality of corner portions (310), the number of the buffer blocks (400) is plural, and one buffer block (400) is mounted to each of the corner portions (310).

4. The inertial measurement unit according to claim 3, characterized in that the circuit board (300) is a rectangular plate body, the circuit board (300) has four corner portions (310), the number of the buffer blocks (400) is four, and the four buffer blocks (400) are mounted at the four corner portions (310), respectively.

5. Inertial measurement unit according to claim 3, characterised in that the damping block (400) is provided with a snap groove (401), the corner section (310) and the snap groove (401) snap fitting.

6. The inertial measurement unit according to claim 5, characterized in that the corner portion (310) is recessed towards the middle of the circuit board (300) to form a notch (311), the snap-in groove (401) fitting in the notch (311).

7. The inertial measurement unit according to claim 5, characterized in that the snap-in groove (401) is an L-shaped groove, or a U-shaped groove or an arc-shaped groove.

8. The inertial measurement unit of claim 6, wherein the buffer block (400) has a first side wall (410) and a second side wall (420) facing away from the snap-in groove (401), the first side wall (410) and the second side wall (420) are distributed at an included angle, the circuit board (300) has a first wall surface (312) and a second wall surface (313), and the first wall surface (312) and the second wall surface (313) are located on both sides of the notch (311);

wherein the first sidewall (410) and the second sidewall (420) are coplanar with the first wall (312) and the first wall (312), respectively.

9. The inertial measurement unit of claim 3, wherein the length of the buffer block (400) in the thickness direction of the circuit board (300) is greater than the thickness of the circuit board (300).

10. The inertial measurement unit of claim 1, wherein the case (100) comprises a first housing (110) and a first boss (120), the first boss (120) is connected to the first housing (110), the cover (200) covers the first housing (110), the cover (200) and the first housing (110) together define the mounting cavity, the first boss (120) is located in the mounting cavity, and the buffer block (400) abuts between the first boss (120) and the cover (200).

11. The inertial measurement unit according to claim 10, characterized in that the cover (200) comprises a second housing (210) and a second boss (220), the second boss (220) and the second housing (210) are connected, the second housing (210) is fitted to the first housing (110), the second housing (210) and the first housing (110) jointly define the mounting chamber, the second boss (220) is located in the mounting chamber, and the buffer block (400) abuts between the first boss (120) and the second boss (220).

12. The inertial measurement unit of claim 11, wherein the first boss (120) and the first housing (110) are integrally formed, and the second boss (220) and the second housing (210) are integrally formed.

13. The inertial measurement unit of claim 11, wherein a first fastener (10) is provided on the first housing (110) and a screw-fitting hole is provided on the second housing (210), the screw-fitting hole and the first fastener (10) fitting to fixedly connect the first housing (110) and the second housing (210).

14. Inertial measurement unit according to claim 11, characterized in that the first housing (110) and the second housing (210) are snap-fitted.

15. The inertial measurement unit of claim 1, further comprising a circuit board body (600) and a processor (700), the circuit board body (600) being mounted within the cartridge body (100), the processor (700) being mounted to the circuit board body (600);

the circuit board body (600) is arranged on one side of the circuit board (300) far away from the cover body (200).

16. The inertial measurement unit of claim 15, further comprising a first board-to-board connector (30) and a second board-to-board connector (40), the first board-to-board connector (30) being mounted to the circuit board (300), the second board-to-board connector (40) being mounted to the circuit board body (600), the first board-to-board connector (30) and the second board-to-board connector (40) being electrically connected.

17. The inertial measurement unit of claim 15, further comprising an external data connector (800), the external data connector (800) being mounted to the circuit board body (600).

18. Inertial measurement unit according to claim 15, characterized in that the circuit board (300) and the circuit board body (600) are electrically connected by a flexible circuit board or a cable.

19. The inertial measurement unit according to claim 10, characterized in that it further comprises a circuit board body (600) and a second fastener (20), four through holes being provided on said circuit board body (600), said second fastener (20) penetrating said through holes to fix said circuit board body (600) within said first casing (110).

20. The inertial measurement unit according to claim 19, characterized in that the number of the first bosses (120) is plural, the circuit board body (600) being located between the plural first bosses (120).

21. Inertial measurement unit according to claim 1, characterized in that the buffer block (400) is made of a rubber material.