U.S. patent application number 10/540639 was filed with the patent office on 2006-03-16 for modular unit comprising a bush for chain drives.
This patent application is currently assigned to INA-SCHAEFFLER KG. Invention is credited to Reinhard Koch.
Application Number | 20060054121 10/540639 |
Document ID | / |
Family ID | 32667822 |
Filed Date | 2006-03-16 |
United States Patent
Application |
20060054121 |
Kind Code |
A1 |
Koch; Reinhard |
March 16, 2006 |
Modular unit comprising a bush for chain drives
Abstract
A modular assembly is provided having a metal bushing (1), which
is inserted into a plastic support body (3) for a tensioning rail
or a guiding rail (4) of a chain drive of an internal combustion
engine which axially contacts the motor housing (5), and is mounted
via a screw extending through the bushing (1). The bushing (1)
according to the invention is provided as a rotationally
symmetrical body and is inserted into a bore hole of the support
body (3), the bushing is provided at its end section, facing the
motor, with a circular step (10) for a transition to a reduced
exterior diameter, by which it is axially supported on a step (11)
provided with a reduced interior diameter inside the mounting hole
of the support body (3).
Inventors: |
Koch; Reinhard; (Wachenroth,
DE) |
Correspondence
Address: |
VOLPE AND KOENIG, P.C.
UNITED PLAZA, SUITE 1600
30 SOUTH 17TH STREET
PHILADELPHIA
PA
19103
US
|
Assignee: |
INA-SCHAEFFLER KG
INDUSTRIESTRASSE 1-3
HERZOGENAURACH
DE
91074
|
Family ID: |
32667822 |
Appl. No.: |
10/540639 |
Filed: |
January 23, 2004 |
PCT Filed: |
January 23, 2004 |
PCT NO: |
PCT/EP04/00536 |
371 Date: |
June 23, 2005 |
Current U.S.
Class: |
123/90.17 |
Current CPC
Class: |
F16H 7/18 20130101; F01L
1/02 20130101; F16H 2007/0872 20130101; F01L 2301/00 20200501; F16H
7/20 20130101 |
Class at
Publication: |
123/090.17 |
International
Class: |
F01L 1/34 20060101
F01L001/34 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 25, 2003 |
DE |
103 02 876.5 |
Claims
1. An assembly comprising a metal bushing (1) which is inserted
into a plastic supporting body (3) for a tensioning rail (4) or a
guiding rail (4) of a chain drive of an internal combustion engine
and being mounted by a screw extending through the bushing (1) to
and axially contacting a motor housing (5), the bushing (1)
comprises a rotationally symmetrical body and is inserted into a
mounting hole of the supporting body (3) with an end section facing
the motor being provided with a circular step (10) for a transition
to a reduced exterior diameter, by which the bushing is axially
held to a step (11) provided with a reduced interior diameter,
located inside the mounting hole of the supporting body (3).
2. An assembly according to claim 1, wherein the support body (3)
with the mounting hole is surrounded by the guiding rail or
tensioning rail (4) formed from plastic.
3. An assembly according to claim 1, wherein the bushing (1), is
used at a tensioning rail (4), and inside the mounting hole a gap
(12) is provided to allow pivoting of the support body (3) around a
bushing axis.
4. An assembly according to claim 1, wherein the mounting hole of
the support body (3) is a reference bore (6) or a primary mounting
hole.
5. An assembly according to claim 4, wherein a secondary mounting
hole is provided and is formed as an oblong hole (7) in the
supporting body (3) in addition to the reference bore (6).
6. An assembly according to claim 5, wherein a bead (14) is located
on a wall region of the reference bore (6) and/or of the oblong
bore (7), and is received in a circular groove (13) of the inserted
bushing (1).
Description
BACKGROUND
[0001] The invention relates to a modular unit comprising a metal
bushing, which is inserted into a plastic supporting body for a
tensioning rail or a guiding rail of a chain drive of an internal
combustion engine and mounted to the engine by way of a screw
passing through the bushing, contacting it axially.
[0002] In order to mount plastic tensioning rail or guiding rails
for chain drives either fixing screws or bushings are used, with
the bushings being pressed into the plastic supporting body or sunk
in using an ultrasound process. This is necessary because of the
fact that without the bushing the plastic would flow under the load
of the screw and the screw could no longer provide any preload.
Consequently, it would release during operation. For tensioning
rails, usually a screw is used with its exterior diameter being
smooth, and on which the rail can pivot without much wear.
[0003] In order for the known bushings to remain in their position
in the supporting bodies of guiding rails, frequently knurls are
arranged at their exterior diameters in an expensive fashion. A
preliminary assembly of the screws for the tensioning rail is
hardly possible. Another problem arises in guiding rails having two
or more mounting positions. Here, at least one of the mounting
positions is provided in the form of an oblong hole or an oversized
bore in order to compensate for component tolerances and heat
expansion. This reduces the precision of the positioning of the
rail.
[0004] From publication DE 43 41 019 A1 a modular unit of the
above-mentioned type is known, which has the disadvantage that the
bushings are required in two differently constructed versions, i.e.
one metal bushing for the support of the tensioning rail and one
mounting bushing for a guiding rail.
SUMMARY
[0005] The invention is based on the object to develop a bushing,
which can be used both in tensioning rails as well as in guiding
rails. Here, several bushings of identical design are to be used so
that it is possible, e.g., to allocate one bushing in a primary
mounting hole, formed as a bore, and to allocate another
identically designed bushing in an oblong hole. Additionally, such
an identically designed bushing should be suitable for the pivotal
support of a tensioning rail. The bushing should be of simple
production and additionally should secure the rails in the
direction of the axis of the bushing. Commonly standard screws are
to be used for mounting the rails. Furthermore, the bushing is to
be designed such that the possibility of faulty assembly is
excluded.
[0006] This object is attained according to the invention due to
the bushing being provided as a rotationally symmetrical body,
inserted into a mounting hole of the supporting body, with its end
section facing the motor being provided with a circular step for
the transition to a reduced exterior diameter, by which it is
axially held to a step provided on the inside of the mounting hole
of the supporting body with a reduced interior diameter. Such a
bushing can be used in numerous applications and components due to
its simple design, so that the numbers to be produced can be
respectively large. The bushings are clamped into the support body
of the rails, their assembly is therefore possible without any
great expense. No additional tension is applied into the plastic
component in the embodiment according to the invention, as e.g.
occurring in force-fitted bushings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] An exemplary embodiment of the invention is shown in the
drawing and will be explained in greater detail in the following.
Shown are:
[0008] FIG. 1 a perspective view of a guiding rail having two
mounting holes and a bushing and a screw, above each mounting hole,
in an exploded view;
[0009] FIG. 2 an enlarged section of the guiding rail having a
mounting hole provided as an elongated hole and a bushing inserted
therein;
[0010] FIG. 3 a cross-section through the mounting area of a
tensioning rail at a motor housing.
[0011] FIG. 4 a part of a guiding rail according to FIG. 1, shown
in section taken along a plane extending through the axes of the
bushings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0012] A bushing 1 is provided formed as a rotationally symmetrical
body. In the axial direction, a through bore for a mounting screw 2
is located in the center of the bushing 1. The bushing 1 serves to
mount a supporting body 3 for a guiding rail or tensioning rail 4
to a motor housing 5. The supporting body is provided with a
primary mounting hole, formed as a reference bore 6, and a
secondary mounting hole, formed as an oblong hole 7, that is spaced
apart therefrom. As clearly discernible from FIGS. 1 and 4, the
guiding rail 4 is provided with two mounting holes, with one
bushing 1 being provided for each mounting hole. Here, the bushing
1 for the reference bore 6 and the bushing 1 for the oblong hole 7
are formed with an identical design. The bushing 1, which is
located in the oblong hole 7, can be shifted parallel to its axis
in a displacement direction 8. A minimal clearance 9 is present
between the bushing 1 and the oblong hole 7 laterally to the
displacement direction 8. The through bore of the bushing 1 may
also be provided with a minimal clearance in reference to the screw
2. This considerably improves the tolerance situation with respect
to the prior known solutions.
[0013] In the end region of the bushing 1, one circular step 10 is
provided for the transfer to a reduced exterior diameter. The step
is used in cooperation with the supporting body 3 of the tensioning
rail 4 shown in FIG. 3 such that it is held during the screw-on
process at the support body 3 at a step 11 formed in the mounting
hole. In reference to the supporting body 3, the bushing 1
maintains a slight gap 12, so that the rail always remains pivotal.
This design of the contour ensures the rail to be positioned in the
axial direction of the motor. A minimum gap is also possible
between the screw 2 and the bore of the bushing 1.
[0014] Furthermore, at the exterior diameter of the bushing 1, a
groove 13 is provided in the form of a cut. This cut is
advantageously located off-centered, so that the bushing 1 cannot
be mounted in the wrong direction.
[0015] In each bore section of the supporting body 3 for the rail,
one small bead 14 is provided formed at the wall, which partially
reduces the diameter of the bore. Instead of a continuous bead 14,
individual bead sections may be provided as well. The bead 14
engages the groove 13 of the bushing 1 when the bushing 1 is
inserted into the mounting hole of the supporting body 3. In this
manner the bushing 1 is protected from falling out during
transport. The width of the cut is to be selected such that the
bead 14 is positioned openly in the grove 13 when assembled.
[0016] In order to ensure the freedom of movement for the
supporting body 3 and the tensioning rail 4, the bushing 1 is
provided at its axial end with protrusions 15 and 16, so that it
protrudes beyond the length of the component of the support body 3
in the area of the mounting hole. When the bushing 1 is used at the
guiding rail 4, the step 11 is formed such that the step 10 of the
bushing 1 ensures play-free support body 3 at the motor housing
5.
[0017] In oblong holes in the support bodies 3 of guiding rails 4,
a small bead 14 may also be provided as a protrusion at the wall in
the longitudinal direction of such a mounting hole. After the
bushing 1 has been clamped in, it can be freely displaced in the
longitudinal direction of the oblong hole 7, i.e. axially parallel
in reference to the bushing, until it is aligned with the bore for
the screw 2 in the motor block 5. Due to the fact that the bore of
the bushing 1 is only slightly larger than the gap of the screw 2,
and additionally the bushing 1 has snapped into the support body 3
of the guiding rail 4, additional positioning tolerances may be
reduced here. Here, it is also to be observed: If the bushing 1 is
screwed on the step 10 jams the step 11 in the plastic of the
support body 3 of the rail so that a secure fixation is
ensured.
[0018] Due to the fact that the bushing 1 according to the
invention concerns a rotationally symmetrical component without any
protrusions, its exterior diameter may be cut without any center.
This is considerably more efficient than the insertion cuts of
collar screws. This advantage may be used particularly for
tensioning rails.
[0019] The assembly of the bushing 1 can occur using simple
assembly devices, e.g., a hand lever press. Compared thereto,
expensive machines are necessary for an insertion using the
ultrasound process. Additionally, the ultrasound process requires a
large amount of energy.
[0020] When using the bushing 1 at the tension rails 4, the step 11
of the support body 3 is provided such that between the support
body 3 and the motor housing 5 some clearance is provided. In this
case, play develops between the head of the mounting screw 2 and
the support body 3, as discernible from FIG. 3, so that the rail is
pivotal.
[0021] When using the bushing 1 at the guiding rail 4, the step 11
of the support body 3 is advantageously provided such that it can
be jammed to the motor housing 5 by the step 10 of the bushing
1.
[0022] Identically designed bushings may also be used for a
tensioning rail and for a guiding rail. The bushings are clamped to
the rails and remain there. The bead and the groove are embodied
such that the bushing preliminarily mounted in the support body can
be moved freely due to the clearance in the bead/groove
arrangement. Prior to the assembly no axial fixation of the rail at
the motor housing occurs, this arrangement serves merely for
transportation safety. By the embodiment of the bushing according
to the invention a best-fitting shape and a high surface quality
can be guaranteed. The bushings are completely covered by the rail
body.
LIST OF REFERENCE CHARACTERS
[0023] 1 bushing [0024] 2 mounting screw [0025] 3 supporting body
[0026] 4 guiding rail or tensioning rail [0027] 5 motor housing,
motor block [0028] 6 reference bore [0029] 7 oblong hole [0030] 8
direction of displacement [0031] 9 minimum clearance [0032] 10 step
[0033] 11 stop [0034] 12 gap [0035] 13 groove [0036] 14 bead [0037]
15 protrusion [0038] 16 protrusion
* * * * *