WO2023186928A1

WO2023186928A1 - An openable roof assembly

Info

Publication number: WO2023186928A1
Application number: PCT/EP2023/058048
Authority: WO
Inventors: Joseph Burrows
Original assignee: Jaguar Land Rover Limited
Priority date: 2022-03-29
Filing date: 2023-03-28
Publication date: 2023-10-05
Also published as: GB2617101A; GB202204437D0

Abstract

Embodiments of the present invention provide an openable roof assembly (1) for a vehicle (2). The openable roof assembly (1) comprises a frame (3) configured to support an openable roof panel (4). The frame (3) comprises: a front member (5) and a rear member (6); a first side member (9) and a second side member (10), each of the first side member (9) and the second side member (10) extending from the front member (5) to the rear member (6); and an intermediate member (11) extending from the first side member (9) to the second side member (10) at a location between the front member (5) and the rear member (6). The openable roof assembly (1) also comprises a mass damper (16) mounted to the intermediate member (11) of the frame (2). The mass damper (16) comprises a moveable mass (19) that is moveable relative to the intermediate member (11) such that vibrations in the openable roof assembly (1) are dampened during use.

Description

AN OPENABLE ROOF ASSEMBLY

TECHNICAL FIELD

The present disclosure relates to an openable roof assembly and particularly to an openable roof assembly comprising a mass-damper. Aspects of the invention relate to an openable roof assembly, a vehicle comprising an openable roof assembly and a method of assembling an openable roof assembly.

BACKGROUND

During use of a vehicle, a driver and any passengers in a cabin of the vehicle hear sounds arising from, for example, movement of the vehicle through its surroundings and from an engine or motor of the vehicle. The volume and frequency of the sound audible within the cabin varies depending on factors such as road surface, vehicle speed and the tyres on the vehicle. If the frequency of the sound is the same as a frequency mode of the cabin, resonance occurs, and a booming noise is produced within the cabin. The comfort of the driver and passengers in the vehicle is reduced if the volume of the booming noise is high, for example, greater than 50 dB. In such cases, the booming noise is also associated with oppressive pressure within the cabin.

A roof assembly is a part of the vehicle that is sensitive to the frequency modes of the cabin. The volume of the booming noise in the cabin increases if the roof assembly, or a part of the assembly, is excited by the frequency modes of the cabin. The roof assembly may possess a resonance which couples with the frequency modes of the cabin. A vehicle having roof assembly with one or more openable roof panels is more susceptible to louder booming noises in the cabin compared to a vehicle having a roof assembly with a fixed or unopenable roof panel due to the openable roof assembly being comparably less stiff.

It is an object of embodiments of the invention to at least mitigate one or more of the problems of the prior art. In particular, the embodiments of invention seek to provide an openable roof assembly which improves driver and passenger comfort.

SUMMARY OF THE INVENTION

Aspects and embodiments of the invention provide an openable roof assembly, a vehicle comprising an openable roof and a method of assembling an openable roof assembly. According to an aspect of the invention, there is provided an openable roof assembly for a vehicle comprising: a frame configured to support an openable roof panel; and a mass damper mounted to the frame, the mass damper comprising a moveable mass that is moveable relative to the frame such that vibrations in the roof assembly are dampened during use.

Including a mass damper in the roof assembly of a vehicle reduces the likelihood of booming noises that are discomforting to a driver or passenger being created in the cabin of the vehicle during use. As a vehicle including the roof assembly is driven, the moveable mass of the mass damper moves relative to the frame. This movement decouples the roof assembly from the frequency modes of the cabin of the vehicle thereby reducing the amplitude of vibration of the roof assembly at the cabin frequency modes. The mass damper reduces the vibration of the roof assembly, so reducing or eliminating excitation of the modes of the cabin of the vehicle by the roof assembly vibration. This decreases the volume of noise in the cabin compared the noise in a vehicle with an openable roof assembly that does not include a mass damper and improves drive and passenger comfort.

In certain embodiments, the moveable mass may be coupled to the frame on a first side of the moveable mass and on a second side of the moveable mass opposing the first side. Coupling the movable mass to the frame on two sides reduces the risk of the moveable mass pivoting about one of its sides which may adversely affect the dampening of vibrations.

The first side of the moveable mass may be coupled to the frame at a first location and at a second location that is spaced apart from the first location positioned. Additionally or alternatively, the second side of the moveable mass may be coupled to the frame at a first location and at a second location that is spaced apart from the first location positioned. Coupling the movable mass to the frame at two locations this way reduces the risk of the moveable mass pivoting or twisting about the points where the moveable mass is coupled to the frame which may adversely affect the dampening of vibrations.

In certain embodiments, the mass damper may extend away from the frame such that the moveable mass is configured to partially overlap the openable roof panel when the openable roof panel engages the frame. Overlapping the moveable mass with the openable roof panel improves dampening of vibrations of the openable roof panel. The mass damper may comprise a plurality of mounting members configured to moveably couple the moveable mass to the frame, wherein each mounting member comprises an elastomeric material. In such embodiments, the elastomeric material of the mounting members enables the moveable mass to move relative to the frame. The stiffness of the material may be chosen to provide the desired dampening effect. The elastomeric material may comprise polyurethane or a thermoplastic elastomer (TPE). Each mounting member may have a hardness from 30 to 70 Shore, or a hardness of 60 Shore.

In certain embodiments, each mounting member may form a push fit with the moveable mass. As such, the mounting member may be secured to the mass damper without requiring a large number of components or a complex assembly.

In certain embodiments, the mass damper may comprise a bracket to which the moveable mass moveably coupled, the bracket may be mounted to the frame so that the moveable mass is coupled to the frame via the bracket. Providing a bracket reduces the modifications required to the intermediate member of the frame in order to couple the moveable mass to the frame. In such embodiments, each mounting member may extend though the bracket and into the moveable mass to suspend the moveable mass from the bracket. As such, coupling of the moveable mass to the bracket may be simplified. In certain embodiments, each mounting member may form a push fit with the bracket.

According to an aspect of the invention, there is provided an openable roof assembly for a vehicle comprising: a frame configured to support an openable roof panel, the frame comprising: a front member and a rear member; a first side member and a second side member, each of the first side member and the second side member extending from the front member to the rear member; and an intermediate member extending from the first side member to the second side member at a location between the front member and the rear member; and a mass damper mounted to the intermediate member of the frame, the mass damper comprising a moveable mass that is moveable relative to the intermediate member such that vibrations in the openable roof assembly are dampened during use. Including a mass damper in the roof assembly of a vehicle reduces the likelihood of booming noises that are discomforting to a driver or passenger being created in the cabin of the vehicle during use. As a vehicle including the roof assembly is driven, the moveable mass of the mass damper moves relative to the frame. This movement decouples the roof assembly from the frequency modes of the cabin of the vehicle thereby reducing the amplitude of vibration of the roof assembly at the cabin frequency modes. This decreases the volume of noise in the cabin compared the noise in a vehicle with an openable roof assembly that does not include a mass damper thereby improving driver and passenger comfort. Mounting the mass damper to the intermediate member places the mass damper in the location where it is most effective at damping vibrations in the roof assembly.

In certain embodiments, the moveable mass may be coupled to the frame on a first side of the moveable mass and on a second side of the moveable mass, wherein the first side of the moveable mass faces the front member and the second side of the moveable mass faces the rear member. Thus, the first and second sides are opposing sides of the moveable mass. Coupling the movable mass to the frame on two sides reduces the risk of the moveable mass pivoting about one of its sides which may adversely affect the dampening of vibrations.

The first side of the moveable mass may be coupled to the intermediate member at a first location positioned towards the first side member of the frame and a second location positioned towards the second side member of the frame. Additionally or alternatively, the second side of the moveable mass may be coupled to the intermediate member at a first location positioned towards the first side member of the frame and a second location positioned towards the second side member of the frame. Coupling the movable mass to the frame at two locations this way reduces the risk of the moveable mass pivoting or twisting about the points where the moveable mass is coupled to the frame which may adversely affect the dampening of vibrations.

The frame may be configured to support a front roof panel between the front member and the intermediate member and a rear roof panel between the rear member and the intermediate member. The mass damper may extend towards the rear member and/or the front member such that the moveable mass partially overlaps at least one of the rear roof panel and the front roof panel to dampen vibrations in the respective roof panel when the respective roof panel is engaged with the intermediate member. Overlapping the moveable mass with the front and/or rear roof panel in this way improves dampening of vibrations of the panel.

In certain embodiments, the openable roof assembly may comprise the front and rear roof panels. The front roof panel may be openable, and the rear roof panel may be in a fixed position relative to the frame.

In certain embodiments, the mass damper may comprise a plurality of mounting members configured to moveably couple the moveable mass to the intermediate member of the frame, wherein each mounting member comprises an elastomeric material. In such embodiments, the elastomeric material of the mounting members enables the moveable mass to move relative to the frame. The stiffness of the material may be chosen to provide the desired dampening effect. The elastomeric material may comprise polyurethane or a thermoplastic elastomer (TPE). Each mounting member may have a hardness from 30 to 70 Shore, or a hardness of 60 Shore.

Each mounting member may form a push fit with the moveable mass. As such, the mounting member may be secured to the mass damper without requiring a large number of components or a complex assembly.

In certain embodiments, the mass damper may comprise a bracket to which the moveable mass moveably coupled and wherein the bracket is mounted to the intermediate member so that the moveable mass is coupled to the intermediate member via the bracket. Providing a bracket may reduce the modifications required to the intermediate member of the frame in order to couple the moveable mass to the frame. In embodiments comprising the plurality of mounting members, each mounting member may extend though the bracket and into the moveable mass to suspend the moveable mass from the bracket. As such, coupling of the moveable mass to the bracket is simplified. Each mounting member may form a push fit with the bracket.

In certain embodiments of either of the above-described aspects of the invention, the openable roof assembly may comprise the openable roof panel, wherein the openable roof panel overlays and substantially covers the frame to serve as an outer surface of a vehicle comprising the assembly. The mass damper is particularly effective in such roof assemblies where the stiffness of the roof assembly is reduced as the frame does not surround the roof panels. In certain embodiments of either of the above-described aspects of the invention, the moveable mass may have a mass of 2.5 kg or less. The effect of mass damper at damping vibrations varies with the mass of the movable mass. The inventors found that there are diminishing returns in dampening effect for moveable masses over 2.5 kg. Alternatively, the moveable mass may have a mass of 1.9 kg or less. A mass of 1.9 kg provides sufficient dampening of vibrations whilst fitting within space constraints in the roof assembly of a vehicle.

According to an aspect of the invention, there is provided a vehicle comprising an openable roof assembly as described above. The vehicle provides the same advantages as the above-described openable roof assembly.

According to an aspect of the invention, there is provided a method of assembling an openable roof assembly comprising: assembling a frame configured to support an openable roof panel; mounting a mass damper to the frame wherein the mass damper comprises a moveable mass that is moveable relative to the frame such that vibrations in the roof assembly are dampened during use.

According to an aspect of the invention, there is provided a method of assembling an openable roof assembly comprising: assembling a frame configured to support an openable roof panel, wherein assembling the frame comprises; providing a front member and a rear member; providing a first side member and a second side member, each of the first side member and the second side member extending from the front member to the rear member; and extending an intermediate member from the first side member to the second side member at a location between the front member and the rear member mounting a mass damper to the intermediate member of the frame wherein the mass damper comprises a moveable mass that is moveable relative to the intermediate member such that vibrations in the roof assembly are dampened during use. The method produces an openable roof assembly having the same advantages as the above-described openable roof assembly.

Within the scope of this application, it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 shows a perspective view of the underside of a part of an openable roof assembly in accordance with an embodiment of the invention;

Figure 2 shows a vehicle in accordance with an embodiment of the invention;

Figure 3 shows a cross-section of the openable roof assembly of Figure 1 ;

Figure 4 shows a mass damper of the openable roof assembly of Figure 1 ; and

Figure 5 shows a graph of the performance of openable roof assemblies.

DETAILED DESCRIPTION

Figure 1 shows an openable roof assembly 1 according to an embodiment of the invention and Figure 2 shows a vehicle 2 comprising the openable roof assembly 1. The roof assembly 1 comprises a frame 3 configured to support an openable roof panel 4 on the vehicle.

In the embodiment shown in the Figures, the frame 3 comprises a front member 5 and a rear member 6. As shown in Figure 2, when the roof assembly 1 is installed on a vehicle 2, the front member 5 is positioned towards the front 7 of the vehicle 2 and the rear member 6 is positioned towards the rear 8 of the vehicle 2.

The frame 3 also comprises a first side member 9 and a second side member 10. As shown in Figure 2, when the roof assembly 1 is installed on a vehicle 2, the first side member 9 is positioned at a first lateral side of the vehicle 2 and the second side member 10 is positioned at a second lateral side of the vehicle 2, opposite the first lateral side. Each of the first side member 9 and the second side member 10 extends from the front member 5 to the rear member 6. The first and second side members 9, 10 may be fixed to the front and rear members 5, 6 in any suitable manner. For example, the members 5, 6, 9, 10 may be fixed together by welding, bonding or mechanical fastening. As shown in Figure 2, frame 3 is sized and shaped to cover the vehicle 2 roof so that the openable roof assembly 1 forms the entirety of the vehicle roof. However, the frame 3 is not limited to this shape. The frame 3 and the front 5, rear 6 and side 9, 10 members may be any suitable sized and shape for use on a vehicle 2.

As shown in Figures 1 and 2, the frame 3 comprises an intermediate member 11. The intermediate member 11 extends from the first side member 9 to the second side member 10 at a location between the front member 5 and the rear member 6. As such, the intermediate member 11 divides the frame 3 in two such that the frame 3 has a front opening 12 and a rear opening 13. The intermediate member 11 may increase the stability and stiffness of the frame 3.

The intermediate member 11 may be fixed to the first and second side members 9, 10 in any suitable manner. For example, the members 9, 10, 11 may be fixed together by welding, bonding or mechanical fastening. In the non-limiting embodiment of Figure 2, the intermediate member 11 is positioned closer to the rear member 6 than the front member 6. However, in alternative embodiments, the intermediate member 11 may be in a different position, such as equidistant from the front and rear members 5, 6.

Each member 5, 6, 9, 10, 11 of the frame 3 may be formed from any suitable material. Non-limiting examples include aluminium, magnesium and steel. Each member 5, 6, 9, 10, 11 of the frame 3 may be formed as stamped members or may be extruded.

The frame 3 is configured to support an openable roof panel 4. In the embodiment shown in the Figures, the frame 3 is configured to support a front openable roof panel 4 between the front member 5 and the intermediate member 11 .

The front roof panel 4 is configured to move between a closed position shown in Figures 1 and 2 and an open position shown in Figure 3. In the closed position, the front roof panel 4 extends from the intermediate member 11 of the frame 3 to the front member 5 and from the first side member 9 to the second side member 10. That is, the front roof panel 4 engages each of the intermediate member 11 , front member 5, first side member 9 and second side member 10 to close front opening 12 in the frame 3.

When the front roof panel 4 is in the open position, the front roof panel 4 no longer engages the front member 5 and the intermediate member 11. Thus, enabling the interior of the vehicle 2 to be open to its surroundings. The front roof panel 4 may be moved reward relative to the frame 3 from the closed position to the open position.

Any conventional means may be used to support the front roof panel 4 on the frame 3 and to move the front roof panel 4 between the open and closed positions. For example, the first and second side members 9, 10 may each comprise a track (not shown). Each track may cooperate with a slider (not shown) to which the front roof panel 4 may be mounted. The sliders may be configured to move the front roof panel 4 along the track between the closed and open positions. The sliders may be connected to a motor (not shown) configured to move the sliders.

As shown in the Figures, the roof assembly 1 comprises a rear roof panel 14. The rear roof panel 14 is fixed relative to the frame 3. That is, the rear roof panel 14 is not openable. As shown in Figure 2, the rear roof panel 14 extends from the rear member 6 of the frame to the intermediate member 11 and from the first side member 9 to the second side member 10. Thus, the rear roof panel 14 engages each of the intermediate member 11 , rear member 6, first side member 9 and second side member 10 to close rear opening 13 in the frame 3. The rear roof panel 14 may be bonded and/or bolted to the frame 3.

The front and rear roof panels 4, 14 are arranged so that the front roof panel 4 engages the rear roof panel 14 when the front roof panel 4 is in the closed position. As shown in Figure 3, the rear roof panel 14 is provided with a first seal 15a arranged to engage the front roof panel 4 when it is in the closed position. The first seal 15a seals the front roof panel 4 to the rear roof panel 14 to protect against ingress of water into the vehicle 2 with the front roof panel 4 is closed. A second seal 15b is provided on the intermediate member 11 for engaging the front roof panel 4.

The roof assembly 1 shown in the Figures is a top loaded roof assembly. The front and rear roof panels 4, 14, are arranged on top of the frame 3 so that the frame 3 supports the panels 4, 14 from underneath when installed. As such, the roof panels 4, 14 overlay and substantially cover the frame 3 to serve as an outer surface of the vehicle 2.

The front roof panel 4 and/or the rear roof panel 14 may be at least partially transparent such that a driver or passenger in the vehicle 2 can see through the panels 4, 14 out of the roof assembly 1. As such, the roof assembly 1 may provide a panoramic view to the driver and any passengers in the vehicle 2. The front roof panel 4 and the rear roof panel 14 may be tinted to reduce visibility and manage heat transfer in and/or out of the vehicle cabin. Each of the front and rear roof panels 4, 14 may comprise one or more sheets of material as shown in Figure 3.

The openable roof assembly 1 comprises a mass damper 16. A mass damper 16 may also be known as a mass dampener, dynamic absorber or vibration absorber, and the principle of operation will be briefly described. The mass damper 16 operates as a spring-mass system and functions by modifying the vibrations of the harmonically excited roof assembly 1. Such a spring-mass system comprises a movable mass 19 coupled via one or more spring 21 to the roof assembly 1. The spring-mass system has a natural frequency determined by the mass of the movable mass 19 and the stiffness of the spring(s) 21. Therefore, the natural frequency of the spring-mass system is tuned to the modal frequency of the roof assembly so that the spring-mass system absorbs or dissipates the vibration energy of the roof assembly 1 . The springs 21 may also include a damping element to absorb energy across a wider frequency range. For example, springs 21 may be made of any resilient material, such as metals, polymeric and elastomeric materials including natural and synthetic rubber, and combinations of these materials. Elastomeric springs typically provide a greater degree of damping than metal springs, but both elastomeric and metal springs may be useful in providing the required technical effect depending on the frequency range of the harmonic behaviour of the openable roof assembly 1 .

In the embodiment shown in the Figures, the mass damper 16 comprises a bracket 17 which is mounted to the intermediate member 11 of the frame 3. As shown in Figure 2, the mass damper 16 comprises a plurality of bolts 18 for mounting the bracket 17 to the intermediate member 11. In certain embodiments, the bracket 17 may alternatively or additionally be welded to the frame 3. The bracket 17 may be formed from a metal. For example, the bracket 17 may comprise die cast zinc. A movable mass 19 is moveably coupled to the frame 3 by the bracket 17. Thus, whilst the bracket 17 is fixedly mounted to the frame 3 the movable mass 19 can move relative to the frame 3 and the bracket 17. In certain embodiments, the movable mass 19 may be formed from a metal. For example, the movable mass 19 may comprise die cast zinc.

As shown in Figures 1 and 4, the bracket 17 and the moveable mass 19 are elongate. As such, they have a similar profile to the intermediate member 11 of the frame 3. As shown in Figure 3, the intermediate member 11 , bracket 17 and movable mass 19 can be concealed by the same piece of trim 20 in the vehicle 3.

The mass damper 16 comprises a plurality of mounting members, or springs, 21 for moveably coupling the backet 17 and the moveable mass 19. In the embodiment shown in the Figure, the mounting members 21 are shaped as hollow truncated cones. That is, the mounting members 21 taper from a base 22 to a truncated end 23.

To couple the moveable mass 19 to the bracket 17, each mounting member 21 is arranged to extend though the bracket 17 and into the moveable mass 19. As shown in Figure 3, each mounting member 21 extends through an aperture 24 in the bracket 17 and into an aperture 25 in the moveable mass 19 that is aligned with the aperture 24 in the bracket 17. The aperture 25 in the moveable mass 19 has a smaller diameter than the aperture 24 in the bracket 17. Each mounting member 21 is resilient and, in the non-limiting embodiment shown in the Figures, comprises an elastomeric material so that the mounting members 21 act like springs to moveably couple the movable mass 19 and the bracket 17. In certain non-limiting embodiments, the elastomeric material may comprise polyurethane or a thermoplastic elastomer (TPE). The stiffness of the elastomeric material may be chosen depending on the mass of the moveable mass 19 and to allow for the required movement of the moveable mass 19 relative to the bracket 17 and frame 3. In certain non-limiting embodiments, each mounting member 21 may have a hardness from 30 to 70 Shore. Each mounting member 21 may have a hardness of 60 Shore which may to dampen vibrations of the openable roof assembly at 46 Hz.

The outer surface of each mounting member comprises a first 26 and a second 27 circumferentially extending indent. The diameter of the mounting member 21 in the first indent 26 is substantially the same as the diameter of the aperture 25 in the moveable mass. The diameter of the mounting member 21 to either side of the first indent 26 is greater that the diameter of the aperture 25 in the moveable mass 36. Likewise, the diameter of the mounting member 21 in the second indent 27 is substantially the same as the diameter of the aperture 24 in the bracket 17. The diameter of the mounting member 21 to either side of the second indent 27 is greater that the diameter of the aperture 24 in the bracket 17. As such, each mounting member 21 forms a push fit with each of the moveable mass 19 and the bracket 19 to secure each mounting member 21 in place.

The first and second indents 26, 27 are spaced apart from each other on the outer surface of the mounting member 21. As such, the moveable mass 19 is held away from the bracket 17 by the mounting members 21 and the moveable mass 19 is able to move without contacting the bracket 17.

As shown in Figures 1 and 3, the moveable mass 19 is disposed between the bracket 17 and the intermediate member 11. The bracket 17 is arranged to surround three sides of the movable mass 19. The bracket 17 extends parallel to a first side 28 of the moveable mass 19 which faces the front member 5 of the frame 3 and a second opposing side 29 of the movable mass 17 which faces the rear member 6 of the frame 6. The bracket extends across an underside 30 of the movable mass 19. Mounting members 21 are arranged to couple the moveable mass 19 to the bracket 17 on both the first side 28 and the second side 29 of the moveable mass 19. As such, the risk of the moveable mass 19 pivoting relative to the bracket 17 about one of the first and second sides 28, 29 is reduced.

On the first side 28 of the moveable mass 19, the moveable mass 19 is coupled to the bracket at a first location 31a positioned towards the first side member 9 of the frame 3 and a second location 32a positioned towards the second side member 10 of the frame 3. In the embodiment shown Figures 1 and 3, two mounting members 21 are used to couple the moveable mass 19 to the bracket 17 at the first location 31a and the second location 32a. Coupling the moveable mass 19 to the bracket 17 at multiple spaced apart locations 31a, 32a, rather than only at one location, reduces the risk of the movable mass 19 pivoting or rotating about each mounting member 21. In the same way, the second side 29 of the moveable mass 19 is coupled to the bracket 17 at two spaced apart locations. As shown in Figures 1 and 3, the first and second locations 31a, 32a, on the first side of the movable mass are offset from those 31 b, 32b on the second side 29 of the movable mass 19. Furthermore, in the non-limiting embodiment shown in the Figures, the positioning of the mounting members 21 on the first and second sides 28, 29 of the moveable mass 19 helps to constrain horizontal movement (i.e. parallel to the ground when the roof assembly is installed in a vehicle) of the moveable mass 19 relative to the bracket 17 and frame 3 whilst allowing the moveable mass 19 to move vertically relative to the bracket 17 and frame 3. However, the positioning of the mounting members 21 is not limited to the arrangement shown in the Figures. In alternative embodiments, the mounting members 21 may be positioned to allow or constrain movement of the moveable mass relative to the bracket 17 and the frame 3 in different directions. For example, the mounting members may be positioned to help constrain vertical movement of the moveable mass 19 relative to the bracket 17 and frame 3 whilst allowing the moveable mass 19 to move horizontally relative to the bracket 17 and frame 3. Furthermore, the mounting members 21 may be positioned to allow or constrain motion of the moveable mass 19 in directions other than vertical and horizontal directions. The orientation of the mass damper 16 and allowable movement of the moveable mass 19 relative to the roof assembly 1 may be chosen to suit the behaviour characteristics of the roof assembly to which the mass damper is mounted.

Providing the openable roof assembly 1 with a mass damper 16 having a moveable mass 19 that can move relative to the frame 3 enables vibrations in the roof assembly 1 to be dampened during use. As the vehicle 2 comprising the openable roof assembly 1 is driven, the moveable mass 19 of the mass damper 16 moves relative to the intermediate member 11 of the frame 3. This movement decouples the roof assembly 1 from the frequency modes of the cabin of the vehicle 2. Vibration of the roof assembly 1 at the frequency modes of the cabin is therefore significantly reduced compared to vibration in a roof assembly without a mass damper 16. In particular, it is vertical movement (i.e. in a direction perpendicular to the ground) of the movable mass 19 which is most effective to dampen vibrations in the roof system 1 at frequency modes of the cabin. This reduction in vibration results in a decrease in the volume of the booming noise in the cabin as shown in Figure 5.

Figure 5 shows, as a function a frequency, the noise at the front seats within cabins of vehicles having different openable roof assemblies. The solid line 33 which has a maximum at approximately 45 dBA represents the noise within the vehicle having the openable roof assembly comprising the mass damper. The other lines 34, 35, 36 which have maxima at approximately 48 dBA are for vehicles having openable roof assemblies which do not include mass dampers. Thus, using the mass damper 16 reduces the volume of noise within the cabin. The cabins for the vehicles shown in Figure 4 have a frequency mode at around 36 to 38 Hz, as can be seen from the Figure the presence of the mass damper 16 reduces the noise at 36 to 38 Hz by at least 3 dBA. Therefore, a vehicle 2 comprising mass damper 16 in the roof assembly 1 is less susceptible to booming noises that are discomforting to a driver or passenger within the cabin of the vehicle 2 compared to a vehicle without a mass damper in the roof assembly.

As shown in Figure 3, the mass damper 16 extends towards the rear member 6 so that the moveable mass 19 partially overlaps the rear roof panel 14. As such, a portion of the moveable mass 19 is disposed vertically beneath a front edge 37 of the rear roof panel 14 when the roof assembly 1 is installed on a vehicle 2. In the same way, the mass damper 19 also extends towards the front member 5 so that it will partially overlap the front roof panel 4 when the front roof panel 4 is in the closed position engaging the intermediate member 11 . The overlap of the moveable mass 19 with the front and rear roof panels 4, 14 improves dampening of vibrations in the respective roof panel 4, 14 when the respective roof panel 4, 14 is engaged with the intermediate member 11.

The amount by which vibrations in the openable roof assembly 1 are dampened depends on the mass of the moveable mass 19. In certain embodiments, the moveable mass 19 may have a mass less than or equal to 2.4 kg. The inventors found that there were diminishing returns in dampening effect for masses over 2.4 kg. In certain embodiments, the moveable mass 19 may have a mass less than or equal to 1.9 kg. A mass of 1.9 kg provides sufficient dampening of vibrations whilst easily fitting within packaging constraints in the vehicle 2.

According to an embodiment of the invention, there is also provided a method of assembling the above-described openable roof assembly 1 . The method comprises assembling the frame 3 configured to support the openable roof panel 4 and mounting the mass damper 16 to the frame 3. As described above, the mass damper 16 comprises the moveable mass 19 that is moveable relative to the frame 3 such that vibrations in the roof assembly are dampened during use. To provide the assembly 1 shown in Figures 1 to 3, assembling the frame 3 comprises providing the front member 5 and the rear member 6, providing the first side member 9 and the second side member 10. Each of the first side member 9 and the second side member 10 extends from the front member 5 to the rear member 6. Assembling the frame 3 also comprises extending the intermediate member 11 from the first side member 9 to the second side member 10 at a location between the front member 5 and the rear member 6. Additionally, the method comprises mounting the mass damper 16 to the intermediate member 11.

The front 5, rear 6 and side members 9, 10 may be formed as one piece. Alternatively, these members 5, 6, 9, 10 may be formed separately and fixed together in any suitable manner. The intermediate member 11 may be fixed to the first and second side members 9, 10 in any suitable manner. Non-limiting suitable methods for fixing together of the members include welding, bonding or mechanical fastening.

The method may further comprise providing and installing any or all of the features described above with reference to the openable roof assembly 1 of Figures 1 to 4.

The skilled person will appreciate that the invention is not limited to the abovedescribed embodiments and various modifications can be made within the scope of the appended claims.

For example, in the above described embodiment, the mass damper 16 is mounted to the intermediate member 11 of the frame 3. The inventors found that mounting the mass damper 16 to the intermediate member 11 resulted in the most effective damping of vibrations in the roof assembly 1. However, the mass damper 16 is not limited to being mounted to the intermediate member 11 and may be mounted to one or more of the other members 5, 6, 9, 10 of the frame 3. In such embodiments, the mass damper 16 may extend away from the respective frame member 5, 6, 9, 10 such that the moveable mass 19 partially overlaps the roof panel or panels adjacent to the frame member 5, 6, 9, 10. For example, the mass damper 16 may be mounted to the front member 5 of the frame 3. The mass damper 16 may extend towards the rear member 6 to the frame 3 such that the moveable mass 19 partially overlaps front roof panel 4.

In the above described embodiment, the openable roof assembly 1 is a top loaded roof assembly. The mass damper 16 is particularly effective in such assemblies because the stiffness of the roof is reduced as the frame 3 does not surround the roof panels 4, 14. However, the mass damper 16 is not limited to being mounted to this type of roof assembly. In certain embodiments, the mass damper 16 may be mounted to the frame of a bottom loaded roof assembly. In a bottom loaded roof assembly, a frame is configured to surround each of the roof panels such that when the assembly is installed on a vehicle the frame and roof panels together form an outer surface of a vehicle. The bottom loaded roof assembly may comprise the frame configured to support an openable roof panel. The frame may have substantially the same structure as the frame described above for the top loaded roof assembly (i.e. the frame may comprise a front member, a rear member, side members and an intermediate member) and may be configured to support front and rear roof panels. In the same manner as described above for the top loaded roof assembly, the mass damper may be mounted to the intermediate member of the frame or a different member of the frame.

In certain embodiments, the mass damper 16 may not include the bracket 17. Rather, the moveable mass 19 may be coupled directly to the intermediate member 11 (or other member of the frame 3). In such embodiments, the moveable mass 19 may be coupled directly to the intermediate member 11 (or other member of the frame 3) by the plurality of mounting members 21.

In certain embodiments, the moveable mass 19 may be moveably coupled to the bracket 17 or frame 3 by different mounting means. For example, the mounting members may be substantially cylindrical in shape. The mounting members may be solid. The mounting member may comprise one or no circumferentially extending indents. Alternatively, any suitable mounting means may be used to the moveable couple the moveable mass to the bracket or frame.

In certain embodiments, the frame 3 may support a different number of roof panels. For example, the frame 3 may be configured to support a single openable roof panel. Alternatively, the frame 3 may be configured support three or more roof panels. In such embodiments, the frame 3 may comprise an additional intermediate member such that each roof panel is separated from an adjacent roof panel by member extending from the first side member to the second side member.

In certain embodiments, the rear roof panel 14 may be openable, and the front roof panel 4 may be fixed. In certain embodiments, both the rear roof panel 14 and the front roof panel 4 may be openable.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed. The claims should not be construed to cover merely the foregoing embodiments, but also any embodiments which fall within the scope of the claims.

Claims

CLAIMS CLAIMS

1. An openable roof assembly for a vehicle comprising: a frame configured to support an openable roof panel, the frame comprising: a front member and a rear member; a first side member and a second side member, each of the first side member and the second side member extending from the front member to the rear member; and an intermediate member extending from the first side member to the second side member at a location between the front member and the rear member; and a mass damper mounted to the intermediate member of the frame, the mass damper comprising a moveable mass that is moveable relative to the intermediate member such that vibrations in the openable roof assembly are dampened during use.

2. An openable roof assembly according to claim 1 , wherein the moveable mass is coupled to the frame on a first side of the moveable mass and on a second side of the moveable mass, wherein the first side of the moveable mass faces the front member and the second side of the moveable mass faces the rear member.

3. An openable roof assembly according to claim 2, wherein the first side of the moveable mass is coupled to the intermediate member at a first location positioned towards the first side member of the frame and a second location positioned towards the second side member of the frame and/or wherein the second side of the moveable mass is coupled to the intermediate member at a first location positioned towards the first side member of the frame and a second location positioned towards the second side member of the frame.

4. An openable roof assembly according to any one of the preceding claims, wherein the frame is configured to support a front roof panel between the front member and the intermediate member and a rear roof panel between the rear member and the intermediate member.

5. An openable roof assembly according to claim 4, wherein the mass damper extends towards the rear member and/or the front member such that the moveable mass partially overlaps at least one of the rear roof panel and the front roof panel to dampen vibrations in the respective roof panel when the respective roof panel is engaged with the intermediate member.

6. An openable roof assembly according to claim 4 or 5, comprising the front and rear roof panels.

7. An openable roof assembly according to any one of claims 4 to 6, wherein the front roof panel is openable, and the rear roof panel is in a fixed position relative to the frame.

8. An openable roof assembly according to any one of the preceding claims, wherein the mass damper comprises a plurality of mounting members configured to moveably couple the moveable mass to the intermediate member of the frame, wherein each mounting member comprises an elastomeric material.

9. An openable roof assembly according claim 8, wherein each mounting member forms a push fit with the moveable mass.

10. An openable roof assembly according to any one of the preceding claims, wherein the mass damper comprises a bracket to which the moveable mass moveably coupled and wherein the bracket is mounted to the intermediate member so that the moveable mass is coupled to the intermediate member via the bracket.

11. An openable roof assembly according to claim 10, when dependent on claim 8 or 9, wherein each mounting member extends though the bracket and into the moveable mass to suspend the moveable mass from the bracket.

12. An openable roof assembly according to any one of the preceding claims, comprising the openable roof panel, wherein the openable roof panel overlays and substantially covers the frame to serve as an outer surface of a vehicle comprising the assembly.

13. An openable roof assembly according to any of the preceding claims, wherein the moveable mass has a mass of 2.5 kg or less or wherein the moveable mass has a mass of 1.9 kg or less.

14. A vehicle comprising an openable roof assembly according to any one of the preceding claims.

15. A method of assembling an openable roof assembly comprising: assembling a frame configured to support an openable roof panel, wherein assembling the frame comprises: providing a front member and a rear member; providing a first side member and a second side member, each of the first side member and the second side member extending from the front member to the rear member; and extending an intermediate member from the first side member to the second side member at a location between the front member and the rear member; mounting a mass damper to the intermediate member of the frame wherein the mass damper comprises a moveable mass that is moveable relative to the intermediate member such that vibrations in the roof assembly are dampened during use.