Drum brake support assembly with pre-assembled and installable camshaft actuation assembly

Abstract

The drum brake support assembly (46) includes an axle-side support member (18) and an operating assembly (30) fixed to the axle-side support member (18), the operating assembly (30) including a camshaft (40) extending along the longitudinal axis (L) of the camshaft and a camshaft housing (42) that rotatably supports the camshaft (40) around the longitudinal axis (L), the camshaft (40) having an operating cam (38), the operating cam (38) is the brake shoe of the drum brake (16) The camshaft (40;140;240) is configured to transmit operating torque to (20, 22), and the camshaft (40;140;240) has a drive structure (64;164) spaced apart from the operating cam (38;138) along the longitudinal axis (L) of the camshaft, and the operating assembly (30) has a fixed structure (58), and the fixed structure (58) connects the camshaft housing (42) to a receiving structure (48) of the axle-side support member (18) in order to fix the operating assembly (30) to the axle-side support member (18). The fixed structure (58) and the receiving structure (48) cooperating with the fixed structure (58) to transmit fastening force are configured to connect the operating assembly (30) to the axle-side support member (18) in order to fix the operating assembly (30) to the axle-side support member (18) as an assembled operating assembly (30) with the camshaft (40) received in the camshaft housing.

Description

TECHNICAL FIELD

[0001] The present invention relates to a drum brake support assembly. The drum brake support assembly includes an axle-side support member, and an actuation assembly fixed to the axle-side support member for actuating a drum brake mounted on the drum brake support assembly. The actuation assembly includes a camshaft extending along the longitudinal axis of the camshaft, and a camshaft housing that rotatably supports the camshaft about the longitudinal axis of the camshaft. The camshaft has an actuation cam non-rotatably connected to the camshaft, and the actuation cam is configured to transmit actuation torque to the brake shoes of the drum brake. Furthermore, the camshaft has a drive structure spaced apart from the actuation cam along the longitudinal axis of the camshaft, for introducing actuation torque into the camshaft. This actuation assembly has a fixing structure that connects the camshaft housing to the receiving structure of the axle-side support member, in order to fix the actuation assembly to the axle-side support member.

BACKGROUND ART

[0002] Such a drum brake support assembly is an embodiment relating to axles with drum brakes of the manufacturer Meritor, in particular of the "LM", "LC", "TA", "TC" and "TE" series.

[0003] In known drum brake support assemblies, the camshaft housing is constructed from a plurality of parts. This is because the camshaft provided for actuating the drum brake has a relatively long shape. The first part of the camshaft housing is supported by a brake carrier, which is fixed to the axle body of the rigid axle of the vehicle in the region of the axle journal. The second part of the camshaft housing is fixed to the axle tube of the axle body that supports the axle journal. That is, in this prior art, the axle-side support member is an axle body including an axle journal provided with a brake carrier and an axle tube.

[0004] Although the two camshaft housing portions relating to the prior art can be fixed to the axle-side support member by screws in a way that allows them to be released as specified, they are merely camshaft housing portions and not assembled as a complete working assembly.

[0005] The axle body is used to receive a wheel that is rotatable around the axle. An actuating cam, which is immobile and axially fixed to the camshaft, grips the actuating roller of one of two brake shoes at each of its two curved but parallel to the rotation axis of the camshaft. Each brake shoe supports an actuating roller in its longitudinal end region, and the actuating roller is rotatable both around the axle and around a roller axis parallel to the longitudinal axis of the camshaft. At the other longitudinal end, each brake shoe is supported by the brake carrier only in a state that allows it to pivot both around the axle and around a brake shoe pivot axis parallel to the longitudinal axis of the camshaft. The brake shoes are preloaded toward each other in known ways. The longitudinal ends supporting the actuating rollers are moved away from each other by rotating the camshaft against the preload using the actuating cam, thereby pressing the brake lining, supported on the radially outer surface of the brake shoe, against the inner surface of the brake drum that rotates with the wheel to be braked. The brake drum surrounds the brake shoe radially outward. The brake carrier is fixed by an axle and is therefore capable of supporting the braking torque acting on the brake carrier through the brake lining that contacts the inner surface of the brake drum.

[0006] According to the kinematics of a drum brake actuated by a camshaft, the longitudinal axis of the camshaft is oriented parallel to the longitudinal axis of the axle or axle body. The basic operation of the drum brake described above applies not only to the prior art but also to the axle assembly described in this application, which includes a drum brake support assembly and an axle body supporting the drum brake support assembly.

[0007] In the Meritor axle bodies known to exist as described above, at each bearing position of the drum brake support assembly, the mounting plates protrude radially with respect to the longitudinal axis of the axle body, which is coaxial with the axle, and the mounting plates are oriented perpendicular to the longitudinal axis of the axle body.

[0008] Both known camshaft housing portions have flanges that project in the direction of the actuating cam along the longitudinal axis of the camshaft. Both flanges each pass through a receiving opening in a mounting plate, which is respectively positioned for fixation when the axle assembly is completed. The receiving openings in each known mounting plate are configured such that the flange of the camshaft housing portion can only be inserted into the provided receiving opening in its projecting direction, i.e., along the longitudinal direction of the camshaft. This can only occur if the camshaft is removed, as the actuating cam, due to its radial dimension relative to the longitudinal axis of the camshaft, cannot pass through the receiving opening of the nearest mounting plate.

[0009] After inserting the flange into the receiving opening, the known camshaft housing portion is screwed to the mounting plate with fixing screws that extend parallel to the axle. The fixing screws pass through holes in the mounting plate and are screwed into each fixing opening of the camshaft housing portion. The known mounting plate, with its receiving opening and through opening, each forms a receiving structure. The contact surfaces and fixing openings with female threads of the camshaft housing portion, formed to abut each mounting plate, together with the fixing screws, constitute the fixing structure described at the beginning.

[0010] After the camshaft housing is secured to its mounting plate, the camshaft is inserted into the camshaft housing. As a result, in the completed axle assembly, the mounting plate, positioned in the axle journal area, is located between the camshaft housing (secured to the mounting plate) and the actuating cam. Therefore, in the completed assembly, the actuating cam prevents or obstructs access to the fixing screws that secure the camshaft housing closer to the axle body to its mounting plate.

[0011] As a result, the attachment and removal of the operating assembly from the axle body that supports it always presupposes the assembly of the operating assembly being assembled or disassembled while the operating assembly is being attached or removed. [Overview of the project] [Problems that the invention aims to solve]

[0012] Therefore, the object of the present invention is to describe an operating assembly that facilitates attachment to and, preferably, removal from the axle-side support member. [Means for solving the problem]

[0013] According to the present invention, the problem is solved in the drum brake support assembly described at the beginning, in which the fixed structure and the receiving structure which cooperates with the fixed structure for transmitting fastening force are configured such that the operating assembly, as an assembled operating assembly having a camshaft received in the camshaft housing, is connected to and / or connectable to the axle-side support member for fixing to the axle-side support member.

[0014] According to a preferred embodiment, the aforementioned fixing structure and receiving structure form the sole connection between the actuation assembly and the axle-side support member. This makes it possible to use an actuation assembly with a very short camshaft having a length of, for example, 350 mm or less, preferably 250 mm or less, in which case the actuation cam is not added to the length of the camshaft. This is advantageous in an independent suspension system. In this case, the axle-side support member may be, for example, a brake carrier that can be fixed to the axle journal or axle tube. In this case, the camshaft housing is preferably integrally molded or has at least one housing portion that rotatably supports the camshaft.

[0015] To provide sufficient length for the rotating bearing, the camshaft preferably has a length of at least 100 mm, preferably at least 150 mm, and particularly preferably at least 200 mm. Therefore, the particularly preferred length range for the camshaft is 200 mm to 250 mm, but lengths other than those mentioned above should not be ruled out.

[0016] However, this does not preclude the use of conventional operating assemblies with longer camshafts fixed to the axle body at two bearing positions, which may also be used in accordance with the present invention. The first bearing position, closer to the wheel to be braked, is preferably formed on the brake carrier, and the second bearing position, further away from the wheel to be braked, is preferably located on the axle tube of a commonly used rigid axle. In this case, the camshaft housing may be a single unit or comprise multiple parts, preferably two parts. The camshaft housing may have one or more (preferably two if multiple) housing portions that rotatably support the camshaft.

[0017] The actuation assembly is pre-assembled when the camshaft is rotatably received within the camshaft housing along with an actuation cam that is fixed non-rotatably, preferably axially, to the camshaft. Particularly preferable is that the camshaft, along with its actuation cam, is rotatably received within the camshaft housing in an operable state, thereby eliminating the need to adjust the camshaft at least in its relative position along the longitudinal axis of the camshaft with respect to the camshaft housing after the actuation assembly has been placed on the axle-side support member.

[0018] With regard to drum brake support assemblies, it is essential to always consider whether the operating assembly could be connected to the axle-side support member as a pre-assembled assembly; that is, whether the operating assembly already existed as a separate entity before being connected to the axle-side support member, or whether the operating assembly was formed, or had to be formed, for the first time when its components were attached to the axle-side support member.

[0019] Basically, it is sufficient to permanently connect the assembled operating assembly to the axle-side support member, for example, by a material-bonding connection. This applies when disassembly is not meaningful as a result of technical or economic considerations. However, material-bonding connections, such as welding, are not very desirable because they carry a high risk of thermal distortion, which necessitates repair work. To facilitate repair of the drum brake support assembly, it is preferable that the operating assembly be removably connectable to and / or connected to the axle-side support member in a predetermined manner, depending on the observed condition of the drum brake support assembly, so that it can be removed again from the axle-side support member without damaging the member including the fastening means.

[0020] The drive structure may be any torque transmission structure on the camshaft, such as a keyway profile or a tooth profile. The drive structure may be a member that is immobilely connected to the camshaft to transmit operating torque, such as an operating lever or gear, which in the field is called a "slack adjuster".

[0021] Typically, the camshaft housing is located between the actuating cam and the drive structure in the longitudinal portion of the camshaft, completely enclosing the camshaft around its entire circumference in a closed state in this longitudinal portion. Therefore, the camshaft preferably has both of its longitudinal end regions protruding from the camshaft housing.

[0022] Examples of axle-side support members in this application include the brake carrier described above, which is configured to pivotably support the brake shoes of a drum brake. Alternatively, the axle-side support member may be an axle body including an axle journal or axle tube or generally an axle journal and an axle tube supporting the axle journal, and may optionally include a brake carrier fixed to the axle body.

[0023] The possibility of placing the operating assembly as an assembled unit on the axle-side support member, and preferably being able to remove it again from the support member, offers not only clear advantages in the assembly of the entire operating assembly and the axle assembly supporting it, but also advantages in the machining of the operating assembly and its components. For example, the components of the operating assembly can be finished by machining with just one clamping operation.

[0024] In the prior art, the camshaft housing is often integrally molded with the brake carrier or axle body, or irremovably connected to one of the aforementioned components. Furthermore, the brake carrier has a coaxial through-hole offset laterally from the camshaft housing, i.e., laterally from the longitudinal axis of the camshaft, for fixing the brake carrier to the axle journal or axle tube. In the configuration of the prior art described above, the camshaft housing, irremovably connected to the brake carrier or axle body, cannot be finished in a single clamping operation.

[0025] In an assembled axle assembly, the longitudinal axis of the camshaft typically extends parallel to the axle and / or parallel to the longitudinal axis of the axle body supporting the actuation assembly. Therefore, according to a simple, and therefore particularly preferred, embodiment of the present invention, the actuation assembly, together with the camshaft and actuation cam, is attached to the axle-side support member in a pre-assembled state and can be released from the support member again, provided that the receiving structure has a recess such that a portion of the actuation assembly can be inserted laterally relative to the longitudinal axis of the camshaft by moving the assembled actuation assembly. Preferably, the direction in which the assembled actuation assembly moves into the recess of the receiving structure is perpendicular to the longitudinal axis of the camshaft.

[0026] Basically, the portion of the camshaft housing that is received in the recess of the receiving structure may be any arbitrary portion of the camshaft housing, such as a fixing flange. However, according to the first preferred embodiment, the portion of the actuation assembly is a circumferential portion of the camshaft housing. That is, preferably, the camshaft may be at least largely formed as a tubular member, or may at least comprise a portion of a tubular member. This tubular member or portion of the tubular member can completely circumferentially enclose a part of the camshaft in a closed state. In this case, a pivot bearing such as a slide bush or a needle bearing may be received on the inner surface of the tubular member or the portion of the tubular member. In this pivot bearing, the camshaft may be supported so as to be rotatable relative to the camshaft housing about the longitudinal axis of the camshaft. The outer surface of the tubular member, as at least a partially prismatic or partially cylindrical outer surface portion, can be easily fitted into the complementary partially prismatic or partially cylindrical recess of the receiving structure. For this purpose, it is sufficient that the radius of the partially prismatic or partially cylindrical recess of the receiving structure matches at least the radius of the partially prismatic or partially cylindrical outer surface portion, taking into account the necessary or desirable tolerances and clearances.

[0027] Although the aforementioned at least partially prismatic or partially cylindrical outer surface portion is preferred, it is merely an example, and this outer surface portion of the camshaft housing preferably corresponds to a generally complementary shape of the recess on the receiving structure side. Therefore, very generally, the axle-side support member preferably has a fixing portion formed for fixing to the axle body of the vehicle, or at least a part of the axle body, and the recess of the receiving structure is formed so as to expand in the direction away from the fixing portion or the axle body. The inner diameter of the recess once obtained no longer becomes any smaller as it moves further away from the fixing portion or the axle body, but may in some circumstances remain constant. Preferably, the recess is formed so as to expand exclusively in the direction away from the fixing portion or the axle body. In case of doubt, the inner diameter is measured orthogonally to the direction of travel away from the fixing portion or the axle body.

[0028] Basically, the portion of the camshaft housing that cooperates with the recess of the receiving structure may be continuously curved in the circumferential direction, or / and may be formed in a polyhedral shape, or may have only two abutment surfaces arranged at an angle to each other around a positioning axis parallel to the longitudinal axis of the camshaft, and the abutment surfaces abut against the corresponding mating abutment surfaces of the recess of the receiving structure in the fully assembled state. Due to the shape that widens in the direction away from the fixed portion or the axle body, and in which the inner diameter of the recess does not become any smaller in the direction away from the fixed portion or / and the axle body, the actuating assembly can be reliably moved into the recess in a pre-assembled state in a movement direction transverse, in particular perpendicular, to the longitudinal axis of the camshaft.

[0029] In order to transmit a fastening force that reliably and permanently retains the actuating assembly on the axle-side support member, at least one component of the fixing structure and the receiving structure has at least one fixing means that transmits the fastening force between the fixing structure and the receiving structure. This fixing means is preferably a fixing screw or comprises a fixing screw, but may additionally or alternatively be, or comprise, a grub screw with a nut or a clamp bracket.

[0030] Preferably, in order to establish the connection between the actuating assembly and the axle-side support member, and preferably to release the connection, the fixing means is movable relative to at least one component of the fixing structure and the receiving structure. This movement may be a screwing movement, and / or an insertion movement of the shaft into the opening, or / and a pivoting movement that pivots the clamp bracket as the fixing means onto the bracket bearing and pivots it away from the bracket bearing.

[0031] The fixing means transmits a fastening force that acts, in the assembled state of the drum brake support assembly in which the actuating assembly is operatively connected to the axle-side support member, preferably transversely to the longitudinal axis of the camshaft, particularly preferably in a perpendicular direction.

[0032] This assembled state is identical to the completed assembly state described above.

[0033] To provide sufficient load-bearing capacity for the fastening means for transmitting the required fastening force, at least one fastening means has an elongated shaft that transmits the fastening force in the assembled state of the drum brake support assembly, the shaft extending laterally, preferably perpendicular to the longitudinal axis of the camshaft. The shaft may, to put it simply, be a screw shaft, or / and the shaft of a set screw, and / or part of a clamp bracket.

[0034] According to an alternative, and possibly additional, but equally advantageous, second embodiment, at least one component of the fixing structure and the receiving structure has at least one fixing means for transmitting a fastening force between the fixing structure and the receiving structure, the fixing means being movable at least relative to one component of the fixing structure and the receiving structure for establishing and disengaging the connection between the operating assembly and the axle-side support member. In this second embodiment, in contrast to the above, in the assembled state of the drum brake support assembly, the fixing means transmits a fastening force acting along the longitudinal axis of the camshaft, preferably parallel to the longitudinal axis of the camshaft.

[0035] Further developing the second embodiment described above, at least one fastening means has an elongated shaft that transmits a fastening force in the assembled state of the drum brake support assembly, the shaft extending along the longitudinal axis of the camshaft, preferably parallel to the longitudinal axis of the camshaft. Again, the fastening means may include a screw, a set screw, or both. Basically, a clamp bracket is more readily realized as a fastening means for obtaining a fastening force acting laterally with respect to the longitudinal axis of the camshaft, but a clamp bracket is also conceivable in this type of arrangement.

[0036] In the second embodiment described above, the receiving structure may have a fork-shaped or generally U-shaped mounting plate into which a portion of the camshaft housing can be inserted laterally, preferably perpendicular to, the longitudinal axis of the camshaft. In this case, the legs of the mounting plate defining the opening may be connected to the camshaft housing using a plurality of fixing means having a force acting in a direction parallel to the longitudinal axis of the camshaft, preferably along the longitudinal axis of the camshaft.

[0037] In the case of fastening means using screws, which are preferred for their secure fastening, the fastening structure preferably has at least one tab with at least one fastening opening through which it passes, in order to provide a high-strength connection. In this case, at least one fastening means preferably passes through the fastening opening in the assembled state. Thus, the fastening means can be surrounded by the material of at least one tab all around its circumference, which can form the basis for a high-strength connection between the operating assembly and the axle-side support member. This fastening structure may have multiple tabs, preferably an even number of tabs, and particularly preferably two tabs, in order to apply the fastening force as uniformly as possible on both sides of the camshaft.

[0038] According to a preferred possible embodiment, the tabs are permanently and rigidly connected to the camshaft housing, and particularly preferably integrally molded with the camshaft housing. This not only further reduces the burden of installation, as the correct placement of the tabs for connecting the operating assembly to the axle-side support member occurs simultaneously with the placement of the camshaft housing to the axle-side support member, and particularly simultaneously with the placement of the camshaft housing to the recess of the support member's receiving structure, when the tabs are permanently and rigidly connected to the camshaft housing, preferably integrally molded with the camshaft housing. Furthermore, in a particularly preferred further development, a base for a jointless, and therefore high-strength connection is also provided. Preferably, at least two tabs permanently and rigidly connected to the camshaft housing, preferably integrally molded with the camshaft housing, protrude from the camshaft housing in opposing directions perpendicular to the camshaft longitudinal axis. In the second embodiment described above, the tabs may be formed as fixed flanges surrounding the camshaft longitudinal axis.

[0039] Alternatively, the tab may be formed separately from the camshaft housing on a retaining or clamping member that surrounds the camshaft housing in the assembled state. This has the advantage that the surrounding retaining or clamping member can be dimensionally designed and formed to be suitable for the function of securing the camshaft housing, while the camshaft housing only needs to provide a rotatable bearing for the camshaft.

[0040] To facilitate assembly and enhance operational safety, one of the camshaft housing and the retaining member or clamping member may have a locking structure, and the other member may have a complementary locking structure. In the assembled state, the locking structure and the locking structure cooperate to prevent relative axial movement between the camshaft housing and the retaining member or clamping member along the longitudinal axis of the camshaft. For example, one of the locking structure and the locking structure may have a recess, and the other locking structure may engage with this recess in a shape-connective manner, contrary to the relative axial displacement of the camshaft housing relative to the retaining member or clamping member. The other structure may be a corresponding projection, or, in the case of a retaining member or clamping member, the retaining member or clamping member itself.

[0041] Occasionally, during the braking process, the brake shoe may experience a reaction force acting parallel to the axle and, consequently, parallel to the longitudinal axis of the camshaft at its longitudinal end supporting the actuating roller. This reaction force gradually pushes the brake shoe, at its longitudinal end, towards a virtual longitudinal center plane that is perpendicular to the pitch axis of the vehicle supporting the drum brake support assembly and penetrates the vehicle through its lateral center. Excessive inclination of the brake shoe can prevent the brake lining supported by the brake shoe from making full contact with the inner surface of the brake drum, resulting in an undesirable reduction in braking performance. Further increases in the brake shoe inclination may, in some situations, cause the brake shoe to collide with other components of the drum brake, such as the dust shield.

[0042] To prevent excessive tilting of the brake shoe, the camshaft housing preferably has a contact surface formed along the longitudinal axis of the camshaft, facing the direction of the operating cam, which limits the space in which the brake shoe can move along the longitudinal axis of the camshaft. Preferably, this contact surface structure is formed to contact the operating roller of the brake shoe. In a new state after assembly, the contact surface structure is located at a predetermined distance, i.e., about 1 mm to 4 mm, preferably 1.3 mm to 3 mm, and particularly preferably 1.8 mm to 2.2 mm, from the mating contact portion on the brake shoe side configured to engage with the contact surface structure. This mating contact portion is preferably formed by an operating roller, as described above. The operating roller particularly includes the axis or shaft of the operating roller.

[0043] The contact surface structure may include a single contact surface for contact between the operating rollers of both brake shoes. Alternatively, the contact surface structure may include at least two contact surfaces, with at least one for each operating roller of the brake shoe. The contact surface structure does not necessarily have to have a surface or plane perpendicular to the longitudinal axis of the camshaft, but it is preferable that it does. Such surface may be curved. Additionally or alternatively, the normal vector of the surface structure may be at an angle with a line parallel to the longitudinal axis of the camshaft, but the angle is preferably not greater than 20°, and particularly preferably 15°.

[0044] Furthermore, the present invention relates to an axle assembly comprising a drum brake support assembly configured as described above and further improved.

[0045] In this case, the axle assembly preferably has an axle body that extends along the longitudinal axis of the axle body. Preferably, the longitudinal axis of the axle body extends parallel to the axle of a wheel that is supported or can be supported to rotate by the axle body. The axle-side support member is rigidly connected to the axle body such that the longitudinal axis of the camshaft and the longitudinal axis of the axle body are parallel.

[0046] In an axle assembly, the receiving structure of the axle-side support member, formed as part of the brake carrier or axle body, can be the sole point of fixation of the actuation assembly to the axle body. This allows actuation assemblies, especially those with short camshafts, to be efficiently supported on the axle body. As already mentioned in the introduction regarding the prior art, in the present invention as well, the actuation assembly can be connected to the axle body at multiple fixing points, but usually two support points spaced apart from each other along the longitudinal axis of the camshaft are sufficient.

[0047] In a further specific structural development, the axle body has an axle journal and an axle tube that form the longitudinal end of the axle body. Preferably, the axle journal can support the wheel hub. The longitudinal end of the axle body is located on a first face of the axle-side support member. At least a large portion of the axle tube is located on a second face opposite to the first face of the axle-side support member. In a preferred embodiment, the axle-side support member is the brake carrier described above, which supports not only the receiving structure but also a bearing structure for pivotably supporting the brake shoe.

[0048] A further axle-side support member having a further receiving structure may be positioned on the portion of the axle tube located on the second surface of the axle-side support member. This further axle-side support member may be, for example, an axle tube, or, if the axle journal has a very long shape, the longitudinal end of the axle journal on the axle tube side. In this case, the actuation assembly has a further fixing structure through which the camshaft housing is preferably detachably connected to and / or connected to the further receiving structure in a predetermined manner for fixing the actuation assembly to the axle body. The further fixing structure and the further receiving structure are also preferably configured to be connected to and / or connectable to the axle body for fixing the actuation assembly to the axle body as an assembled actuation assembly having a camshaft received in the camshaft housing.

[0049] The above description of the fixed structure also applies to the further fixed structures mentioned above, and vice versa. Similarly, the above description of the receptive structure also applies to the further receptive structures mentioned above, and vice versa.

[0050] The present invention will be described in detail below with reference to the attached drawings. The following is shown: [Brief explanation of the drawing]

[0051] [Figure 1] This is an exploded perspective view showing a first embodiment of an axle assembly equipped with a drum brake support assembly according to the present invention. [Figure 2] This figure shows the operating assembly used in the drum brake support assembly shown in Figure 1, with the slack adjuster omitted. [Figure 3] Figures 1 and 2 show a longitudinal cross-sectional view of the operating assembly together with the slack adjuster. [Figure 4] This is a side view showing the axle assembly shown in Figure 1. [Figure 5] This figure shows an operating assembly that is an alternative to the operating assembly shown in Figure 2, for use in the drum brake support assembly according to the present invention. [Figure 6] This figure shows a further embodiment of an axle assembly equipped with a drum brake support assembly according to the present invention. [Modes for carrying out the invention]

[0052] The drawings are not to scale, but the proportions of the sizes are accurately reproduced.

[0053] Figure 1 shows a first embodiment of the axle assembly according to the present invention, collectively denoted by reference numeral 10. The axle assembly 10 of Figure 1 is advantageously a short axial length axle assembly and can be used, for example, in an independent suspension system for a commercial vehicle.

[0054] The axle assembly 10 includes an axle journal 12, which in the illustrated embodiment forms an axle body 13. When assembled, a known wheel hub 14 is rotatably positioned around the axle RA at the longitudinal end of the axle journal 12, which faces away from the lateral center of the vehicle supporting the axle assembly 10. The axle RA is also the longitudinal axis of the axle body.

[0055] To decelerate the wheel hub 14 and the wheel mounted on the rotating wheel hub 14 during operation, the axle assembly 10 has a drum brake 16. The drum brake 16 includes a brake carrier 18 that is firmly and immovably connected to the axle journal 12, for example by welding; brake shoes 20 and 22 that are movably supported on the brake carrier 18 and have brake linings 24 and 26 on the outside; a brake drum 28 that surrounds the brake shoes 20 and 22 and rotates with the wheel hub 14; and an actuation assembly 30 for selectively actinguating the drum brake 16.

[0056] While it is assumed that the function of drum brakes is basically known, for completeness, the structure and operation of the drum brake 16 are briefly outlined below: The brake shoes 20 and 22 are received by the brake carrier 18 so as to be rotatable around the brake shoe pivot axis A20 for brake shoe 20 and the brake shoe pivot axis A22 for brake shoe 22, which are parallel to each other and to the axle RA, in their respective bearing end regions 20a and 22a. The preload spring device 32 applies tension to pull the brake shoes 20 and 22 towards each other in the operating end regions 20b and 22b opposite to the bearing end regions 20a and 22a.

[0057] In the operating end regions 20b and 22b, operating rollers 34 and 36 are attached to the brake shoes 20 and 22, respectively, which are rotatable around virtual roller axes R34 and R36 (the operating roller 34 of the upper brake shoe 20 is not shown in Figure 1). The virtual roller axes R34 and R36 are parallel to each other, and also parallel to the axle RA, and consequently to the pivot axes A20 and A22 of the brake shoes.

[0058] In the assembled state, different regions of the circumferential surface 38a of the operating cam 38 are in contact with the outer surfaces of the respective operating rollers 34 and 36. By rotating the operating cam 38 around the rotation axis D, the rollers 34 and 36, and consequently the brake shoes 20 and 22, are able to move away from each other in their operating end regions 20b and 22b, against the pretension of the preload spring device 32, and the brake linings 24 and 26, which are positioned on the outer surfaces of the brake shoes 20 and 22, are pressed against the inner circumferential surface 28a of the brake drum 28.

[0059] The operating cam 38 is firmly connected to the camshaft 40 (see Figure 2), which is not visible in Figure 1, and is rotatable together with the camshaft 40 around the rotation axis D, which is also the longitudinal axis L of the camshaft, in the direction in which the camshaft 40 extends.

[0060] The camshaft 40 is housed in a camshaft housing 42. At the longitudinal end of the camshaft 40, located opposite the actuating cam 38 along the longitudinal axis L of the camshaft, a slack adjuster 44 is non-rotatably connected to the camshaft 40 to introduce actuating torque to the camshaft 40. The slack adjuster 44 is connected in a known manner to a brake actuator, which also acts in a known manner but is not shown, and which rotates the slack adjuster 44, the camshaft 40 (which is rigidly connected to the slack adjuster 44), and the actuating cam 38 around the rotation axis D.

[0061] In the first embodiment, the brake carrier 18, which is a support member on the axle side, and the operating assembly 30 together form a drum brake support assembly 46.

[0062] The brake carrier 18 has a receiving structure 48 used to receive the actuation assembly 30 in the brake carrier 18 and, preferably, to connect to the brake carrier 18 in a detachable manner. In the illustrated embodiment, the receiving structure 48 has a partially cylindrical recess 50, which opens while continuously widening in a direction radially away from the brake carrier 18 or the axle journal 12 or, for example, the axle RA.

[0063] The radius of the partially cylindrical recess 50 matches the radius of the semi-cylindrical portion 42a of the camshaft housing 42 that is received in the recess 50 when the assembly is complete, taking into account a desired fit, such as an intermediate fit.

[0064] In the illustrated example, the receiving structure 48 includes a fixing portion 52 having two flange surfaces 52a and 52b surrounding the recess 50. Each of the flange surfaces 52a and 52b has two blind holes 54 with internal threads for receiving fixing screws 56.

[0065] The fixing screw 56 is part of the fixing structure 58, which further includes two tabs 60a and 60b that project from the camshaft housing 42 in a direction perpendicular to the longitudinal axis L of the camshaft, and are integrated and integrally molded with the camshaft housing 42 in the embodiment of the first embodiment. Each tab 60a and 60b has two through holes 62 that are aligned with blind holes 54 in the flange surfaces 52a and 52b in the assembled state.

[0066] In the assembled state, tabs 60a and 60b face flange surfaces 52a and 52b, and the shaft 56a of the fixing screw 56 passes through the through hole 62 and is screwed into the blind hole 54. The head 56b of the fixing screw 56 abuts against the surfaces of tabs 60a and 60b that are opposite to the flange surfaces 52a and 52b in the assembled state, and thus secures the operating assembly 30 to the brake carrier 18.

[0067] The operating assembly 30 is accessible to the receiving structure 58 in a direction lateral to the longitudinal axis L of the camshaft, particularly perpendicular to it, along arrow M, and is particularly insertable into the recess 50 of the receiving structure 58. The fixing screw 56 transmits a fastening force acting laterally to the longitudinal axis L of the camshaft, particularly perpendicular to it, along its axis 56a.

[0068] With the above structure, the operating assembly 30 is fixed to the brake carrier 18 as a pre-assembled assembly that is ready for operation, and can be removed from the brake carrier 18 again.

[0069] Figure 2 shows an enlarged view of the operating assembly 30. In this figure, the longitudinal end of the camshaft 40 opposite to the operating cam 38 is visible. A portion of the camshaft 40 has a circumferentially extending tooth-like structure 64, such as a keyway profile, which serves as a drive structure for introducing torque to the camshaft 40 using a slack adjuster 44. The slack adjuster 44, which is rigidly connected to the camshaft 40, also constitutes the drive structure in this application.

[0070] On the surface of the camshaft housing 42 facing the axle journal 12 in the assembled state, a protruding projection 66 is formed integrally with the camshaft housing 42 and is used to fix the slack adjuster holder 68 shown in Figure 1.

[0071] Figure 3 shows a longitudinal cross-section of the operating assembly 30 along the cross-section containing the longitudinal axis L of the camshaft. The cross-section is not hatched. What is recognizable is a sliding bearing shell 70 positioned radially between the camshaft housing 42 and the camshaft 40, which reduces the force or torque required to rotate the camshaft 40 within the camshaft housing 42 and avoids undesirable dynamic play.

[0072] Figure 4 is a top view of the axle assembly 10 of Figure 1 in its assembled state, as seen in the direction of arrow M, which also indicates the direction in which the operating assembly 30 is brought closer to the brake carrier 18 in order to assemble the drum brake support assembly 46.

[0073] In a direction that is roughly axial with respect to the longitudinal axis L of the camshaft and the axle RA, the sides of the tabs 60a and 60b facing the wheel hub 14 are formed as stopper surfaces 72a and 72b. The stopper surfaces 72a and 72b are more clearly visible in Figure 2. The stopper surfaces 72a and 72b may be formed as a single continuous surface.

[0074] Contrary to the illustrations in Figures 2, 3, and 4, it is preferable that the stopper surfaces 72a' and 72b' are oriented perpendicular to the longitudinal axis L of the camshaft, as shown by the dashed line in Figure 4.

[0075] The stopper surfaces 72a and 72b, or 72a' and 72b', restrict the lateral movement of the operating end regions 20b and 22b of the brake shoes 20 and 22 parallel to the axle RA or parallel to the longitudinal axis L of the camshaft. When the lateral movement of the operating end regions 20b and 22b becomes sufficiently large, the functional parts of the operating rollers 34 and 36, such as their physical roller axes or roller shafts, come into physical contact with the stopper surfaces 72a and 72b, or 72a' and 72b'. Thus, it is possible to prevent the brake shoes 20 and 22 from tilting excessively with respect to the inclination axis perpendicular to the pivot axis A20 and A22 of the brake shoes on which they are mounted.

[0076] Figure 5 shows a second embodiment of the actuation assembly 130. The viewpoint for observing the actuation assembly 130 corresponds to the viewpoint for observing the actuation assembly 30 according to the first embodiment in Figure 2.

[0077] In the second embodiment of the operating assembly 130, the same reference numerals are used for components and parts of components that are identical and functional to those in the first embodiment, but the number 100 is added to the reference numeral. The second embodiment of the operating assembly 130 will be described below, limited to the differences from the first embodiment, and this description will be clearly referenced in order to explain the operating assembly 130 of the second embodiment.

[0078] In contrast to the first embodiment, the tabs 160a and 160b are not integrally molded with the camshaft housing 142, but are formed separately from the camshaft housing 142 and are formed on a collar 174 that surrounds the camshaft housing 142 along its peripheral edge with respect to the longitudinal axis L of the camshaft. The circumferential angle of the collar 174 surrounding the camshaft housing 142 is between 160° and 180°, preferably 180°.

[0079] The collar 174 and the camshaft housing 142 are locked against relative displacement along the longitudinal axis L of the camshaft by a shape connection engagement. For this purpose, the camshaft housing 142 has a groove 176 that extends in the circumferential direction as a locking structure, and a projection 178 formed on the concave surface of the collar 174 engages with the groove 176 as a mating locking structure.

[0080] The tabs 160a and 160b of the collar 174 each have only one through-opening 162. This merely indicates that the actuation assembly 130 can be secured to the axle-side support member with two screws instead of four. Obviously, the tabs 160a and 160b of the collar 174 may each have two through-openings 162. Similarly, the tabs 60a and 60b integrally molded with the camshaft housing 42 may each have only one through-opening 62.

[0081] For example, if a tab is formed, for instance as a broad-sense hook connection, to connect geometrically to a corresponding structure on the axle-side support member, then one fixing screw may suffice to secure the operating assembly to the axle-side support member. In this case, it is sufficient to provide at least one fixing screw only on the side of the camshaft housing where no direct geometrically connected portion is formed between the tab and the axle-side support member.

[0082] In the second embodiment, the operating assembly 130 does not have a stopper surface corresponding to the stopper surface 72a or / and 72b.

[0083] Figure 6 shows a further embodiment of the axle assembly 210 according to the present invention. In this further embodiment, the same reference numerals are used for the members and parts of the axle assembly 210 that are identical to those of the axle assembly 10 in the first embodiment. These members and parts will not be described again; the descriptions provided in the description of the first embodiment apply to them.

[0084] The components and parts of the axle assembly 210 of this further embodiment, which are structurally modified from the components or parts of the axle assembly 10 of the first embodiment without changing their function within the axle assembly, are given the same reference numerals as in the first embodiment, but with the number 200 added. For the purposes of describing these, the description of the first embodiment will be referenced.

[0085] Components and parts of components used exclusively in axle assembly 210 are denoted by reference symbols in the range between 280 and 299 (including any fractions).

[0086] The essential difference between the axle assembly 210 shown in Figure 6 and the axle assembly 10 shown in Figure 1 is that the axle journal 212 is connected to the axle body 213 using the axle tube 280 of the rigid axle. In the embodiment of Figure 1, the axle journal 12 constitutes the axle body 13 on its own.

[0087] By using a longer axle body 213 compared to the first embodiment, a longer camshaft 240 can also be used. In this case, the operating assembly 230 is no longer fixed to the axle body 213 only via the fixing structure 58 and the axle-side support member 18, but is also fixed via a further fixing structure 282 and a further receiving structure 284. The further receiving structure 284 is located on the axle tube 280, which is an additional axle-side support member.

[0088] The further receiving structure 284 includes a mounting plate 286, which is oriented, for example, as a flat mounting plate 286, perpendicular to the axle RA and protruding from the axle tube 280. The mounting plate 286 forms an additional fixing portion. The further receiving structure 284 also has an additional recess 288, which extends away from the mounting plate 286, which is an additional fixing portion, or away from the axle tube 280, and its inner diameter, once obtained, does not decrease further even if the distance from the axle tube 280 increases.

[0089] The mounting plate 286 has four fixing holes 290 around the further recess 288.

[0090] The further fixed structure 282 has a further camshaft housing 292 positioned axially apart from the camshaft housing 42 along the longitudinal axis L of the camshaft, within which the camshaft 240 is similarly supported so as to be rotatable about its longitudinal axis L. Although the camshaft housing 242 is identical to the camshaft housing 42 of the first embodiment, in Figure 6 it is denoted by the reference numeral 242 because it rotatably supports the camshaft 240 only together with the further camshaft housing 292. Thus, in the embodiment shown in Figure 6, the camshaft housing 242 and the further camshaft housing 292 together constitute a single camshaft housing.

[0091] The additional camshaft housing 292 includes a tab 294 formed as a mounting flange, which has four through holes 296 that align with four fixing holes 290 in the assembled state and are passed through by four additional fixing screws 298. Using the fixing screws 298, the additional camshaft housing 292 is secured to the mounting plate 286 via the tab 294 formed as a mounting flange. For clarity, only two of the through holes 296 are labeled with reference symbols.

[0092] In contrast to the fixing screw 56, the shaft 298a of the further fixing screw 298 extends particularly parallel to the longitudinal axis L of the camshaft.

[0093] Because the inner diameter does not decrease further once it reaches a predetermined size, the additional camshaft housing 292 can also be brought closer to the axle body 213 along the mounting direction M and inserted into the additional recess 288. This allows the entire operating assembly 230 to be brought closer to the axle body 213 along the mounting direction M and connected to the axle body 213.

[0094] It is easy to understand that the fixed structure 30 according to the first embodiment may be configured as a further fixed structure 282, and vice versa. [Explanation of Symbols]

[0095] 10,210 Axle Assembly 12,212 Axle Journal 13,213 Axle body 14 Wheel Hub 16 Drum brakes 18 Brake carrier, axle-side support member 20, 22 Brake shoes 20a, 22a Bearing end area 20b, 22b Working end area 24, 26 Brake linings 28 Brake drum 28a Inner surface 30, 130, 230 Operating Assembly 32 Preload spring device 34, 36 Operating rollers 38. Actuating cam 38a Circumferential surface 40, 240 camshaft 42, 142, 242 Camshaft Housing 42a Semi-cylindrical section 44 Slack Adjuster 46 Drum brake support assembly 48 Receptor Structure 50 recesses 52 Fixed part 52a, 52b Flange surfaces 54 blind holes 56 Fixing screws 56a axis 56b Head 58 Fixed structure 60a, 60b, 160a, 160b tabs 62, 162 through holes 64 Tooth-like structure 66 Protrusion 68 Slack Adjuster Holder 70 Plain bearing shell 72a, 72b, 72a', 72b' Stopper surface 174 Colors 176 Groove 178 Protrusion 280 Axle tube 282 Fixed structure 284 Receptor Structure 286 Mounting plate 288 recesses 290 fixing hole 292 Camshaft Housing 294 tabs 296 Through hole 298 Fixing screws 298a axis A20, A22 Brake shoe pivot axis D Rotation axis L Camshaft Longitudinal Axis M Mounting direction RA axle R34 and R36 virtual roller axes

Claims

1. A drum brake support assembly (46;246) comprising an axle-side support member (18) and an operating assembly (30;230) fixed to the axle-side support member (18), wherein the operating assembly (30;130;230) includes a camshaft (40;140;240) extending along the longitudinal axis (L) of the camshaft and a camshaft housing (42;142;242, 292) that rotatably supports the camshaft (40;140;240) about the longitudinal axis (L), the camshaft (40;140;240) having an operating cam (38;138) non-rotatably connected to the camshaft (40;140;240), the operating cam acting on the brake shoes (20, 22) of the drum brake (16) The camshaft (40;140;240) is configured to transmit torque, and the camshaft (40;140;240) has a drive structure (64;164) for introducing operating torque to the camshaft (40;140;240) along the longitudinal axis (L) of the camshaft, spaced apart from the operating cam (38;138), and the operating assembly (30;130;230) has a fixing structure (58;158;258), and the camshaft housing (42;142;242, 292) is connected (48) to a receiving structure of the axle-side support member (18) to fix the operating assembly (30;130;230) to the axle-side support member (18), in a drum brake support assembly (46;246), The drum brake support assembly (46;246) is characterized in that the fixing structure (58;158;258) and the receiving structure (48) cooperating with the fixing structure (58;158;258) to transmit fastening force are configured such that the operating assembly (30;130;230) is connected to and / or connectable to the axle-side support member (18) for fixing to the axle-side support member (18) as an assembled operating assembly (30;130;230) comprising the camshaft (40;140;240) received in the camshaft housing.

2. The drum brake support assembly (46; 246) according to claim 1, characterized in that the receiving structure (48) has a recess (50), and a portion (42a; 142a) of the operating assembly (30; 130; 230) can enter the recess by movement (M) of the assembled operating assembly (30; 130; 230) in a lateral direction (M) with respect to the longitudinal axis (L) of the camshaft.

3. The drum brake support assembly (46;246) according to claim 2, characterized in that the portion (42a;142a) of the operating assembly (30;130;230) is the circumferential portion (42a;142a) of the camshaft housing (42;242a).

4. The drum brake support assembly (46;246) according to claim 2 or 3, characterized in that the axle-side support member (18) has a fixing portion (52) formed for fixing to the axle body (13;213) of the vehicle and / or the axle body (13;213), and the recess (50) of the receiving structure (48) is formed to widen in a direction away from the fixing portion (52) or the axle body (13;213).

5. A drum brake support assembly (46;246) according to any one of claims 1 to 4, wherein one of the components of the fixing structure (30;130;230) and the receiving structure (48) has at least one fixing means (56) that transmits a fastening force between the fixing structure (30;130;230) and the receiving structure (48), the fixing means (56) is movable relative to at least one of the components of the fixing structure (30;130;230) and the receiving structure (48) to establish and disconnect the connection between the operating assembly (30;130;230) and the axle-side support member (18), and the fixing means (56) transmits a fastening force that acts laterally with respect to the longitudinal axis (L) of the camshaft in the assembled state of the drum brake support assembly (46;246) in which the operating assembly (30;130;230) is operably fixed to the axle-side support member (18).

6. The drum brake support assembly (46;246) according to claim 5, characterized in that at least one of the fastening means (56) has an elongated shaft (56a) that transmits fastening force in the assembled state of the drum brake support assembly (46;246), wherein the shaft (56a) extends laterally with respect to the longitudinal axis (L) of the camshaft.

7. A drum brake support assembly (246) according to any one of claims 1 to 4, wherein one of the components of the fixed structure (282) and the receiving structure (284) has at least one fastening means (298) that transmits a fastening force between the fixed structure (282) and the receiving structure (284), the fastening means being movable relative to at least one of the components of the fixed structure (282) and the receiving structure (284) to establish and disconnect the connection between the operating assembly (230) and the axle-side support member (213), and the fastening means (298) transmits a fastening force acting along the longitudinal axis (L) of the camshaft in the assembled state of the drum brake support assembly (246) in which the operating assembly (230) is operably fixed to the axle-side support member (213).

8. The drum brake support assembly (246) according to claim 7, characterized in that at least one fastening means (298) has an elongated shaft (298a) that transmits fastening force in the assembled state of the drum brake support assembly (246), the shaft (298a) extending along the longitudinal axis (L) of the camshaft.

9. The drum brake support assembly according to claim 6 or 8 (46;246), characterized in that at least one fastening means (56;292) includes a screw, a set screw, or a clamp bracket.

10. A drum brake support assembly (46;246) according to any one of claims 6, 8, or 9, characterized in that a fixing structure (30;130;230) has tabs (60a, 60b;160a, 160b;294), the tabs have at least one fixing opening (62;296) through the tabs (60a, 60b;160a, 160b;294), and at least one fixing means (56;292) passes through the fixing opening (62;296) in the assembled state.

11. The drum brake support assembly (46; 246) according to claim 10, characterized in that the tabs (60a, 60b; 294) are formed to be permanently and rigidly connected to the camshaft housing (42; 242, 292).

12. The drum brake support assembly according to claim 10, characterized in that the tabs (160a, 160b) are formed separately from the camshaft housing (142) on a clamp member (174) that surrounds the camshaft housing (42) in an assembled state.

13. A drum brake support assembly according to claim 12 (46; 246), characterized in that one of the camshaft housing (142) and clamp member (174) has a locking structure (176), and the other member has a complementary locking mating structure (178), and in the assembled state, the locking structure (176) and the locking mating structure (178) cooperate to prevent relative movement of the camshaft housing (142) and the clamp member (174) along the longitudinal axis (L) of the camshaft.

14. Axle assembly (10;210) comprising a drum brake support assembly (46;246) according to any one of claims 1 to 13, wherein the axle assembly (210) has an axle body (13;213) extending along the longitudinal axis (RA) of the axle body, and the axle-side support member (18) is rigidly connected to the axle body (13;213) such that the longitudinal axis (L) of the camshaft and the longitudinal axis (RA) of the axle body extend parallel to each other.

15. The axle body (213) has an axle journal (212) and an axle tube (280) forming the longitudinal end of the axle body (213), the longitudinal end of the axle body (213) is positioned on the first face of the axle side support member (18), at least the majority of the axle tube (280) is positioned on the second face of the axle side support member (18) opposite to the first face, and a further axle side support member (284) having a further receiving structure (286) is positioned on the portion of the axle tube (280) located on the second face of the axle side support member (18), the operating assembly (230) has a further fixing structure (282), and through the further fixing structure, The axle assembly (210) according to claim 14, characterized in that the camshaft housing (42, 292) is connected to and connectable to a further receiving structure (286) for fixing the actuation assembly (230) to the axle body (213), and the further fixing structure (282) and the further receiving structure (286) are also configured such that the actuation assembly (230) is connected to and connectable to the axle body (213) for fixing the actuation assembly (230) as an assembled actuation assembly (230) having the camshaft (240) received in the camshaft housing (242, 292) to the axle body (213).

Images