GB2561392A

GB2561392A - Method for increasing an amount of torque transmittable from a power output end of the crankshaft

Info

Publication number: GB2561392A
Application number: GB1705992.4A
Authority: GB
Inventors: Richard Hector Newton Konrad
Original assignee: Perkins Engines Co Ltd
Current assignee: Perkins Engines Co Ltd
Priority date: 2017-04-13
Filing date: 2017-04-13
Publication date: 2018-10-17
Anticipated expiration: 2037-04-13
Also published as: GB2561392B; GB201705992D0

Abstract

An arrangement, for increasing an amount of torque transmittable from a power output end 108 of a crankshaft 104 of an engine, includes positioning a flywheel 106 in a spaced-apart relation to the output end 108 and positioning a steel load bearing disk 202 between the crankshaft 104 and the flywheel 106. Opposing sides 206, 208 of the disk 202 abut the output end 108 and the flywheel 106. Aligned holes (210, 214, fig 2) in the disk 202 and the flywheel 106 also align with threaded receptacles 212 in the crankshaft 104. Fasteners 204 positioned in the holes (210, 214) engage with the threaded receptacles 212 thereby fastening the flywheel 106 and disk 202 to the output end 108. The disk 202 has a greater diameter than a gear 110. The holes (214) may be tapered. The fasteners 204 and threaded receptacles 212 have a contact pressure of at least 50 MPa. Also claimed is a method for increasing an amount of torque transmittable the output end 108 of the crankshaft 104.

Description

(71) Applicant(s):

Perkins Engines Company Limited (Incorporated in the United Kingdom)

Frank Perkins Way, Eastfield, PETERBOROUGH, PE1 5FQ, United Kingdom (72) Inventor(s):

Konrad Richard Hector Newton (56) Documents Cited:

GB 2345332 A DE 019505520 C1 US 5669820 A

DE 019840217 A1 DE 102008036074 A1 US 20080257676 A1 (58) Field of Search:

INT CL F16C, F16D

Other: ONLINE: EPODOC, WPI (74) Agent and/or Address for Service:

Steven Gahlings

Caterpillar UK Legal Services, Eastfield, Peterborough, Cambridgeshire, PE1 5FQ, United Kingdom (54) Title of the Invention: Method for increasing an amount of torque transmittable from a power output end of the crankshaft

Abstract Title: An arrangement for increasing torque from a crankshaft to a flywheel (57) An arrangement, for increasing an amount of torque transmittable from a power output end 108 of a crankshaft 104 of an engine, includes positioning a flywheel 106 in a spaced-apart relation to the output end 108 and positioning a steel load bearing disk 202 between the crankshaft 104 and the flywheel 106. Opposing sides 206, 208 of the disk 202 abut the output end 108 and the flywheel 106. Aligned holes (210, 214, fig 2) in the disk 202 and the flywheel 106 also align with threaded receptacles 212 in the crankshaft 104. Fasteners 204 positioned in the holes (210, 214) engage with the threaded receptacles 212 thereby fastening the flywheel 106 and disk 202 to the output end 108. The disk 202 has a greater diameter than a gear 110. The holes (214) may be tapered. The fasteners 204 and threaded receptacles 212 have a contact pressure of at least 50 MPa. Also claimed is a method for increasing an amount of torque transmittable the output end 108 of the crankshaft 104.

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-1METHOD FOR INCREASING AN AMOUNT OF TORQUE

TRANSMITTABLE FROM A POWER OUTPUT END OF THE

CRANKSHAFT

Technical Field [0001] The current disclosure relates to engines having a crankshaft defining a power output end located at a rear end of the crankshaft, and more particularly to an arrangement and a method for increasing an amount of torque that can be transmitted from the power output end of the crankshaft.

Background [0002] Engines have been known to typically include a crankshaft for converting a reciprocating motion of one or more pistons into a rotary motion. The crankshaft may include a crank palm at an end of the crankshaft. The crank palm facilitates mounting of a flywheel thereon and serves to transmit power from the crankshaft to the flywheel. In many cases, the crank palm may be located at a rear end of the crankshaft to transmit power into a drive train that is located aft of the engine.

[0003] In cases where the crank palm is located at the rear end of the crankshaft, the crank palm may be designed to have a very small diameter due to compact engine packaging requirements resulting from various space constraints. Also, in some cases, a gear may be mounted circumferentially about the crankshaft and located proximal to the crank palm of the crankshaft requiring that an outer diameter of the crankshaft be smaller than an inner diameter of the gear. Moreover, the smaller diameter of the crank palm may need to be reduced further for allowing the gear to be formed from sufficient volume of material to withstand the torque during operation. As such, this gear may be used to transmit some portion of the torque from the crankshaft in driving, for example, a camshaft and an overhead valve arrangement of the engine.

[0004] However, it has been observed that as the diameter at an end of the crankshaft is reduced to facilitate mounting of the gear circumferentially on the crankshaft and proximal to the crank palm, an amount of torque that can be

-2delivered from the crank palm, taking into account the reduced diameter of the end of the crankshaft, to the flywheel for driving the drive train of a vehicle may consequently reduce. Estimations made by manufacturers have indicated that the amount of torque delivered by the crankshaft into the flywheel is directly proportional to a cube of the diameter associated with the end of the crankshaft.

[0005] Hence, there is a need for an arrangement and a method that improves an amount of torque transmitted from the end of the crankshaft i.e., the crank palm for driving the flywheel so that a desired amount of torque is imparted to the flywheel in driving the drive train of a vehicle.

Summary of the Disclosure [0006] In one aspect of the current disclosure, an arrangement for increasing an amount of torque transmitted from a power output end of the crankshaft includes a flywheel that is positioned in a spaced-apart relation to the power output end of the crankshaft. The arrangement also includes a load bearing disk that is positioned in between the crankshaft and the flywheel such that opposing sides of the load bearing disk are placed in abutment with the power output end of the crankshaft and the flywheel respectively. The load bearing disk includes a first set of holes disposed in mutual alignment with a set of threaded receptacles defined in the power output end of the crankshaft and a second set of holes defined in the flywheel. The arrangement also includes a set of fasteners that are axially positioned within the mutually aligned first and second set of holes together with the threaded receptacles for fastening the load bearing disk and the flywheel to the power output end of the crankshaft.

[0007] In an additional aspect of this disclosure, the load bearing disk is made of steel. Moreover, a diameter of the load bearing disk is one of: less than or equal to a diameter of a gear disposed around a circumference of the crankshaft and located proximal to the power output end of the crankshaft.

[0008] In a further aspect of the present disclosure, the flywheel has a tapered surface adjacent to each hole from the second set of holes defined in the flywheel. The tapered surface extends from a face of the flywheel located adjacent to the load bearing disk and terminates at a region located partway along a width of the

-3flywheel such that the tapered surface is configured to define a first diameter at the face of the flywheel located adjacent to the load bearing disk and a second diameter at the region located partway along the width of the flywheel in which the first diameter is greater than the second diameter.

[0009] In an additional aspect of the present disclosure, the set of fasteners is fastened to the threaded receptacles with a force of at least 50 Megapascal (MPa). [0010] Embodiments disclosed herein are also directed to an engine having a crankshaft with a power output end and employing the arrangement of the present disclosure. Further, embodiments of the present disclosure are also directed to a method for increasing an amount of torque transmitted from the power output end of the crankshaft.

[0011] Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.

Brief Description of the Drawings [0012] FIG. 1 is a side sectional view of an engine block of an engine having a crankshaft rotatably supported therein, the crankshaft defining a power output end located aft of the engine block, according to an embodiment of the present disclosure;

[0013] FIG. 2 is an exploded view of an arrangement for increasing an amount of torque transmitted from the power output end of the crankshaft, according to embodiments of the present disclosure;

[0014] FIG. 3 is an assembled side sectional view of the arrangement, according to embodiments of the present disclosure; and [0015] FIG. 4 is a flowchart of a method for increasing an amount of torque transmitted from the power output end of the crankshaft.

Detailed Description [0016] Reference will now be made in detail to specific aspects or features, examples of which are illustrated in the accompanying drawings. Wherever possible, corresponding or similar reference numbers will be used throughout the drawings to refer to the same or corresponding parts.

--4-[0017] FIG. 1 illustrates an engine 100 having an engine block 102 and a crankshaft 104 rotatably supported by the engine block 102. The engine 100 disclosed herein may be configured for use in, for example, powering a vehicle (not shown) having a rear wheel drive (RWD) in which a drive train of the vehicle may be selectively connected to a flywheel 106 of the engine 100, the flywheel 106 being located aft of the engine block 102 as shown in FIG. 1. Although a vehicle having a RWD is disclosed herein, it may be noted that other types of rotatable loads can be selectively connected to the flywheel 106. For example, the engine 100 shown in FIG. 1 may be used to operatively drive an electrical generator (not shown) or a pump (not shown) that would be located aft of the engine block 102.

[0018] As shown in FIG. 2, the crankshaft 104 includes a power output end 108. A gear 110 is mounted circumferentially to the crankshaft 104 and located proximal to the power output end 108 of the crankshaft 104. It is envisioned that during operation of the engine 100 this gear 110 may be configured to transmit some portion of the power from the crankshaft 104, for example, towards driving a camshaft (not shown) and an overhead valve arrangement 200 (not shown) of the engine 100. However, the camshaft and the overhead valve arrangement 200 is non-limiting of this disclosure. Any type of rotatable load including, but not limited to, pumps, compressors, and the like may be connected to the gear 110 without deviating from the scope of the present disclosure.

[0019] In order to mount the gear 110 to the crankshaft 104, a portion 112 of the crankshaft 104 may be stepped and hence, configured to exhibit a reduced diameter D3 proximal to the power output end 108 of the crankshaft 104. The gear 110 may then be press-fit onto an outer surface 114 of the crankshaft 104 and located proximal to the power output end 108 of the crankshaft 104 i.e., on the portion 112 of the crankshaft 104 that exhibits the reduced diameter D3. The reduced diameter D3 of the portion 112 of the crankshaft 104 could allow the gear 110 to be formed from a sufficient amount of material during manufacture so as to withstand the forces of operation when in use by the engine 100. Also, manufacturers may be able to press-fit the gear 110 onto the portion 112 of the crankshaft 104 exhibiting the smaller diameter D3 for taking into account the —5— various space constraints encountered in regards to engine 100 sizing and engine 100 packing requirements during designing of the engine 100. However, it is envisioned that the reduced diameter D3 of the power output end 108 of the crankshaft 104 may also cause a reduction in the amount of torque being transmitted from the power output end 108 of the crankshaft 104 to the flywheel 106.

[0020] The present disclosure is aimed at increasing the amount of torque transmitted from the power output end 108 of the crankshaft 104 to the flywheel 106 with the help of an arrangement 200 shown in FIGS. 2-3, explanation to which will be made hereinafter.

[0021] With continued reference to FIG. 2, the arrangement 200 is disposed at the power output end 108 of the crankshaft 104 and this arrangement 200 serves to increase the amount of torque transmitted from the power output end 108 of the crankshaft 104 to the flywheel 106. Referring to FIGS. 2 and 3, the arrangement 200 consists of the flywheel 106, a load bearing disk 202, and a set of fasteners 204 that are configured to connect with the power output end 108 of the crankshaft 104.

[0022] According to an embodiment of this disclosure that is best shown in FIG. 3, the flywheel 106 is positioned in a spaced-apart relation to the power output end 108 of the crankshaft 104. The load bearing disk 202 is positioned in between the crankshaft 104 and the flywheel 106 such that opposing sides 206, 208 of the load bearing disk 202 are placed in abutment with the power output end 108 of the crankshaft 104 and the flywheel 106 respectively.

[0023] Also, the load bearing disk 202 includes a first set of holes 210 disposed in mutual alignment with a set of threaded receptacles 212 defined in the power output end 108 of the crankshaft 104 and a second set of holes 214 defined in the flywheel 106 respectively. The set of fasteners 204 are axially positioned within the mutually aligned first and second set of holes 210, 214 together with the threaded receptacles 212 for fastening the load bearing disk 202 and the flywheel 106 to the power output end 108 of the crankshaft 104. As shown in FIGS. 2-3, the fasteners 204 may include, for example, bolts.

--6-[0024] According to an embodiment of this disclosure, the load bearing disk 202 may preferably be made of steel. Moreover, a diameter D of the load bearing disk 202, according to embodiments of this disclosure, would be selected so as to be less than an outer diameter Do of the gear 110. Optionally, in an alternative embodiment, the diameter D of the load bearing disk 202 could be equal to the outer diameter Do of the gear 110. However, with regards to the preceding two embodiments, it may be noted that the diameter D of the load bearing disk 202 would also be selected such that the diameter D of the load bearing disk 202 is greater than the reduced diameter D3 of the power output end 108 of the crankshaft 104. This way, the load bearing disk 202 with the enlarged diameter D could serve as a ‘crank palm’ that is large enough to effectively transmit an increased amount of torque from the crankshaft 104 to the flywheel 106 than if the flywheel 106 were to be conventionally disposed in a direct connection with the power output end 108 of the crankshaft 104 as such a conventional configuration of direct connection between the flywheel 106 and the power output end 108 of the crankshaft 104 with the reduced diameter D3 would limit the amount of torque that could be transmitted from the crankshaft 104 i.e., from the power output end 108 of the crankshaft 104 having the reduced diameter D3 to the flywheel 106.

[0025] Also, in an embodiment of this disclosure, it has been contemplated to fasten the set of fasteners 204 to the threaded receptacles 212 of the crankshaft 104 with a contact pressure of at least 50 Megapascal (MPa) so that with such an amount of contact pressure, the flywheel 106 and the load bearing disk 202 could be firmly secured to the power output end 108 of the crankshaft 104. For instance, the fasteners 204 may be torque-wrenched to engage with corresponding ones of the threaded receptacles 212 with a contact pressure of 55 MPa.

[0026] Additionally or optionally, in a further embodiment as best shown in FIG. 3, the flywheel 106 may be configured to define a tapered surface 216 adjacent to each hole from the second set of holes 214 defined in the flywheel 106. The tapered surface 216 may be configured to extend from a face 218 of the flywheel 106 located adjacent to the load bearing disk 202 and terminate at a

-Ίregion 220 located partway along a width W of the flywheel 106 such that the tapered surface 216 may define a first diameter Di at the face 218 of the flywheel 106 and a second diameter D2 at the region 220 located partway along the width W of the flywheel 106. Moreover, as shown in FIG. 3, the first diameter Di would be greater than the second diameter D2 i.e., DI > D2.

[0027] The tapered surfaces 216 adjacent to the holes 214 on the flywheel 106 provide an increased diameter Di to each hole 214 on the flywheel 106 at its face 218 that is adjacent to the load bearing disk 202 for allowing a load of the fastener 204 i.e., the load from a flange 222 of the bolt to act uniformly on the load bearing disk 202 and therefore, the tapered surfaces 216 could help in enhancing a capability of the load bearing disk 202 to increase the amount of torque transmitted from the power output end 108 of the crankshaft 104 to the flywheel 106. Also, each of the tapered surfaces 216 define a conical recess 224 together with an outer surface 226 of the corresponding fastener 204 i.e., a shank 228 of the bolt. With contact pressure between the fasteners 204 and the threaded receptacles 212 being high i.e., >50 MPa, each of these conical recesses 224 may provide at least some amount of stress relief to the load bearing disk 202 as it elastically deforms under a force of compression resulting from the contact pressure of the fasteners 204 with the threaded receptacles 212 of the crankshaft 104.

[0028] FIG. 4 is a flowchart depicting a method 400 for increasing the amount of torque transmitted from the power output end 108 of the crankshaft 104 to the flywheel 106. As shown in FIG. 4, at step 402, the method 400 includes positioning the flywheel 106 in a spaced-apart relation to the power output end 108 of the crankshaft 104. At step 404, the method 400 includes positioning the load bearing disk 202 between the crankshaft 104 and the flywheel 106 such that opposing sides 206, 208 of the load bearing disk 202 are placed in abutment with the power output end 108 of the crankshaft 104 and the flywheel 106 respectively and in which the first set of holes 210 defined on the load bearing disk 202 is disposed in mutual alignment with the set of threaded receptacles 212 defined in the power output end 108 of the crankshaft 104 and the second set of holes 214 defined in the flywheel 106 respectively.

-8[0029] At step 406, the method 400 includes fastening the load bearing disk 202 and the flywheel 106 to the power output end 108 of the crankshaft 104 using the set of fasteners 204 such that the set of fasteners 204 are axially received within the mutually aligned first and second set of holes 214 and the threaded receptacles 212 to engage with the threaded receptacles 212 of the crankshaft 104.

[0030] As disclosed earlier by way of an embodiment of this disclosure, the step 402 of positioning the load bearing disk 202 between the crankshaft 104 and the flywheel 106 could include positioning a load bearing disk 202 that is made from steel. Also, in a further embodiment of this disclosure, the method 400 could include using the load bearing disk 202 of a diameter D that is less than or equal to the outer diameter Do of the gear 110 disposed around the circumference of the crankshaft 104 and located proximal to the power output end 108 of the crankshaft 104. However, as disclosed earlier in accordance with an embodiment of this disclosure, the diameter D of the load bearing disk 202 is kept larger than the diameter D3 of the power output end 108 of the crankshaft 104 for realizing functions that are consistent with the present disclosure i.e., to serve as a ‘crank palm’ that is large enough to effectively transmit an increased amount of torque from the crankshaft 104 to the flywheel 106 than if the flywheel 106 were to be conventionally disposed in a direct connection with the power output end 108 of the crankshaft 104 as such a conventional connection of the flywheel 106 with the reduced diameter D3 of the crankshaft 104 could limit the amount of torque transmitted from the crankshaft 104 to the flywheel 106.

[0031] In an embodiment of this disclosure, the method 400 may include fastening the set of fasteners 204 to the threaded receptacles 212 with a contact pressure of at least 50 MPa. In a further embodiment of this disclosure, the method 400 may further include defining the tapered surface 216 in the flywheel 106 adjacent to each hole from the second set of holes 214 defined in the flywheel 106 such that the tapered surface 216 extends from the face 218 of the flywheel 106 located adjacent to the load bearing disk 202 and terminates at the region 220 located partway along the width W of the flywheel 106. Further, the tapered surface 216 defined in the flywheel 106 adjacent to each hole 214 may be

--9-configured to have a first diameter Di at the face 218 of the flywheel 106 adjacent to the load bearing disk 202 and a second diameter D₂ at the region 220 located partway along the width W of the flywheel 106. Moreover, as shown in FIG. 3, the first diameter Di would be greater than the second diameter D₂ i.e., D, > D₂.

Industrial Applicability [0032] Embodiments of the present disclosure have applicability for implementation and use in increasing an amount of torque transmitted from the crankshaft 104 into the flywheel 106. With implementation of the arrangement 200 disclosed herein, the power output end 108 of the crankshaft 104 may be rendered with improved torque transmissibility in powering a drive train connected to the engine. Also, with implementation of the arrangement 200 disclosed herein, manufacturers of engines can beneficially offset costs that were typically incurred with use of previously known components such as high grade flywheel materials to help transmit power from the crankshaft into the flywheel. Rather implementation of the arrangement 200 disclosed herein may help render engines to be designed using flywheels made from low-cost materials including, but not limited to, steel, or grey iron or other grades of iron exhibiting similar ductile strength, thereby making engines more economical to manufacture when compared to previously known designs of engines in which expensive high grade flywheel materials were being used in the manufacture of the flywheel. Moreover, manufacturers of engines may also save costs that were previously incurred from manufacturing a crank palm for connecting the flywheel to the crankshaft as with use of embodiments disclosed herein, the present disclosure allows manufacturers to do away with incorporation of a crank palm and instead, connect the flywheel directly with the power output end of the crankshaft.

[0033] Further, the arrangement 200 of the present disclosure may, in use, enhance the ability of the power output end of crankshafts to withstand operational forces better than previously known arrangements in which a flywheel would be directly connected to a crank palm having a reduced diameter as compressive forces resulting from a fastening of the flywheel to the power

-10-output end of the crankshaft is now at least partially borne by the load bearing disk 202 disclosed herein.

[0034] While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.

Global Claims

Claims

What is claimed is:

1. An arrangement (200) for increasing an amount of torque transmittable from a power output end (108) of the crankshaft (104), the arrangement (200) including:

a flywheel (106) positioned in a spaced-apart relation to the power output end (108) of the crankshaft (104);

a load bearing disk (202) positioned in between the crankshaft (104) and the flywheel (106) such that opposing sides (206, 208) of the load bearing disk (202) are placed in abutment with the power output end (108) of the crankshaft (104) and the flywheel (106) respectively, wherein the load bearing disk (202) includes a first set of holes (210) disposed in mutual alignment with a set of threaded receptacles (212) defined in the power output end (108) of the crankshaft (104) and a second set of holes (214) defined in the flywheel (106); and a set of fasteners (204) axially positioned within the mutually aligned first and second set of holes (210, 214) together with the threaded receptacles (212) for fastening the load bearing disk (202) and the flywheel (106) to the power output end (108) of the crankshaft (104).

2. The arrangement (200) of claim 1, wherein the load bearing disk (202) is comprised of steel.

3. The arrangement (200) of claim 1, wherein a diameter (D) of the load bearing disk (202) is one of: less than or equal to a diameter (Do) of a gear (110) disposed around a circumference of the crankshaft (104) and located proximal to the power output end (108) of the crankshaft (104).

4. The arrangement (200) of claim 1, wherein the flywheel (106) has a tapered surface (216) adjacent to each hole from the second set of holes (214) defined in the flywheel (106), the tapered surface (216) extending from a face (218) of the flywheel (106) located adjacent to the load bearing disk (202) and terminating at a region (220) located partway along a width (W) of the flywheel (106).

5. The arrangement (200) of claim 4, wherein the tapered surface (216) is configured to define a first diameter (Di) at the face (218) of the flywheel (106) located adjacent to the load bearing disk (202) and a second diameter (D2) at the region (220) located partway along the width (W) of the flywheel (106).

6. The arrangement (200) of claim 5, wherein the first diameter (Di) is greater than the second diameter (D2).

7. The arrangement (200) of claim 1, wherein the set of fasteners (204) is fastened to the threaded receptacles (212) with a contact pressure of at least 50 Megapascal (MPa).

8. An engine having:

a crankshaft (104) with a power output end (108); and employing the arrangement (200) of claim 1.

9. A method (400) for increasing an amount of torque transmitted from a power output end (108) of the crankshaft (104), the method (400) including:

positioning a flywheel (106) in a spaced-apart relation to the power output end (108) of the crankshaft (104);

positioning a load bearing disk (202) between the crankshaft (104) and the flywheel (106) such that opposing sides (206, 208) of the load bearing disk (202) are placed in abutment with the power output end (108) of the crankshaft (104) and the flywheel (106) respectively, wherein the load bearing disk (202) includes a first set of holes (210) disposed in mutual alignment with a set of threaded receptacles (212) defined In the power output end (108) of the crankshaft (104) and a second set of holes (214) defined In the flywheel (106); and fastening the load bearing disk (202) and the flywheel (106) to the power output end (108) of the crankshaft (104) using fasteners (204) axially received within the mutually aligned first and second set of holes (210, 214) and the threaded receptacles (212) to engage with the threaded receptacles (212).

10. The method (400) of claim 9, wherein positioning the load bearing disk (202) between the crankshaft (104) and the flywheel (106) includes positioning a load bearing disk (202) comprised of steel.

Intellectual

Property

Office

Application No: GB 1705992.4 Examiner: Mike McKinney