JP2020076418A - Torque converter - Google Patents

Abstract

To provide a torque converter capable of reducing stress acting on a basic end portion (root) of a front boss caused by displacement of a crank shaft, and preventing occurrence of cracking starting from the basic end portion of the front boss.SOLUTION: A torque converter 1 includes a front boss 10 substantially formed into a columnar shape and projecting from a central portion of a front cover 21. A notch 10a having a prescribed depth in an axial direction is formed from a top face to a side face of the front boss 10. The notch 10a is formed into the straight shape having a prescribed width in a radial direction through a shaft center when observed from an axial direction of the front boss 10. Further the notch 10a is extended along a direction substantially orthogonal to a reciprocation direction of a piston of an engine 3 to be connected.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a torque converter.

  Conventionally, a torque converter that amplifies engine torque (engine driving force) by utilizing fluid (oil) in combination with a stepped automatic transmission (step AT), a continuously variable transmission (CVT), etc. mounted on a vehicle Is widely used. The torque converter transmits the engine torque through the oil and has a torque amplification function, so that the vehicle can be started smoothly. Further, the torque converter also has a function of absorbing vibration generated by the engine.

  Here, Patent Document 1 discloses a fastening portion structure of a torque converter. More specifically, in this torque converter fastening portion structure, a converter case (front cover) of the torque converter is provided coaxially with the drive plate attached to the end of the crankshaft of the engine, and the drive case is driven from the converter case. A plurality of bolts are provided so as to project in the circumferential direction toward the plate. On the other hand, the drive plate is formed with a bolt insertion hole through which the plurality of bolts are inserted. Then, the drive plate and the converter case are fastened by tightening the bolts inserted through the bolt insertion holes with nuts.

  Further, when the crankshaft of the engine and the torque converter are fastened, a front boss provided at the center of the converter case (front cover) of the torque converter is fitted into a fitting hole formed at the center of the rotation shaft of the end surface of the crankshaft. Shaft center alignment (position alignment) is performed by fitting (pilot boss).

Japanese Patent Laid-Open No. 05-118408

  When the engine is driven after the torque converter is assembled to the crankshaft of the engine as described above, the displacement of the crankshaft due to the engine operation is input as a load to the front boss. If the displacement of the crankshaft is large, the repeated load applied to the front boss increases, and if it exceeds the fatigue strength of the front boss, fatigue fracture may occur. In particular, in the conventional structure, the stress caused by the input load due to the displacement of the crankshaft tends to concentrate on the base end portion (root) of the front boss. For example, if a crack starts from the base end portion of the front boss, However, the crack may reach the inside of the torque converter, causing oil leakage from the torque converter.

  The present invention has been made in order to solve the above problems, and it is possible to reduce the stress acting on the base end portion (root) of the front boss due to the displacement of the crankshaft, and to reduce the base end portion of the front boss. An object of the present invention is to provide a torque converter capable of preventing the occurrence of cracks (fatigue fracture) starting from a starting point.

  The torque converter according to the present invention includes a front boss that is formed in a substantially columnar shape and that is provided so as to project from the center of the front cover. The front boss has a predetermined depth in the axial direction from the top surface to the side surface. It is characterized in that a notch having is formed.

  According to the torque converter of the present invention, the notch having a predetermined depth in the axial direction is formed from the top surface to the side surface of the front boss formed in a substantially columnar shape and projecting from the center of the front cover. Has been done. Therefore, the stress caused by the input load due to the displacement of the crankshaft can be dispersed to the base end portion (root) of the front boss and the bottom portion of the notch. By dispersing the generated stress, the stress at the base end portion of the front boss is reduced, and fatigue fracture of the front boss is prevented. As a result, the stress acting on the base end portion (root) of the front boss due to the displacement of the crankshaft can be reduced, and the occurrence of cracks (fatigue fracture) originating from the base end portion of the front boss can be prevented. It will be possible.

  In the torque converter according to the present invention, it is preferable that the notch is formed in a straight line passing through the axial center and having a predetermined width in the radial direction when viewed from the axial direction of the front boss.

  In this case, the notch is formed in a straight line that passes through the axial center and has a predetermined width in the radial direction when viewed from the axial direction of the front boss, so that the stress caused by the displacement of the crankshaft is effectively prevented. It becomes possible to disperse.

  In the torque converter according to the present invention, it is preferable that the cutout is formed so as to extend along a direction substantially orthogonal to the reciprocating direction of the piston of the engine to be coupled.

  In this case, since the notch is formed so as to extend along a direction substantially orthogonal to the reciprocating direction of the piston of the engine to be coupled, it becomes easy to bend with respect to the stress caused by the displacement of the crankshaft. It becomes possible to disperse the stress more effectively.

  In the torque converter according to the present invention, the depth of the notch in the axial direction is formed to be substantially the same as the depth at which the fitting hole formed in the crankshaft of the engine to be coupled and the front boss are in contact with each other. Is preferred.

  In this case, since the depth of the notch in the axial direction is formed to be substantially the same as the depth at which the fitting hole formed in the crankshaft of the engine to be joined and the front boss are in contact with each other, the displacement of the crankshaft is prevented. It is possible to effectively disperse the resulting stress.

  In the torque converter according to the present invention, even if it is assumed that the depth of the notch in the axial direction extends from the corner of the bottom of the notch as an origin and the angle formed by the axis extends at 45 degrees, Is preferably formed to a depth that does not connect to the inside of the torque converter.

  In this case, even if it is assumed that the depth of the notch in the axial direction extends from the corner of the bottom of the notch at an angle of 45 degrees with the axis, the crack extends to the inside of the torque converter. Since it is formed to a depth that does not connect, even if a crack occurs, it is possible to prevent oil leakage from the torque converter.

  In the torque converter according to the present invention, it is preferable that the predetermined width is set to approximately 1/3 of the diameter of the front boss.

  In this case, since the predetermined width (width of the notch) is set to approximately 1/3 of the diameter of the front boss, it is possible to achieve both strength and flexibility (flexibility) in a well-balanced manner. It is possible to more effectively disperse the stress caused by the displacement of the shaft.

  In the torque converter according to the present invention, it is preferable that the corners of the bottom of the cutout are not chamfered.

  In this case, since the corners of the bottom of the notch are not rounded, stress should be concentrated at the notch of the front boss (that is, the fuse function is exerted), not at the base end (root) of the front boss. Is possible.

  On the other hand, in the torque converter according to the present invention, it is preferable that the base end of the front boss is chamfered along the circumferential direction to be larger than the corner of the bottom of the notch.

  In this case, the base end portion of the front boss is provided with a radius R larger than the corner portion of the bottom portion of the notch along the circumferential direction, so that the stress caused by the displacement of the crankshaft is concentrated on the notch side. It becomes possible.

  In the torque converter according to the present invention, it is preferable that the front boss is fitted into a fitting hole formed in a crankshaft of a 180 ° crank engine when the front boss is joined to the engine.

  In this case, the front boss is fitted in a fitting hole formed in the crankshaft of a 180 ° crank engine (engine in which combustion strokes come at 180 ° intervals), that is, the torque converter according to the present invention is By being combined with a 180-degree crank engine, the stress caused by the displacement of the crankshaft can be more effectively dispersed.

  According to the present invention, the stress acting on the base end portion (root) of the front boss due to the displacement of the crankshaft can be reduced, and the occurrence of cracks (fatigue fracture) originating from the base end portion of the front boss can be prevented. It becomes possible to do.

It is a block diagram showing a schematic structure of a power unit to which a torque converter concerning an embodiment is applied. It is a figure showing the whole torque converter structure concerning an embodiment. It is a perspective view which expands and shows the front boss of the torque converter which concerns on embodiment.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals. Further, in each drawing, the same elements are denoted by the same reference numerals, and duplicate description is omitted.

  First, the structure of the torque converter 1 according to the embodiment will be described with reference to FIGS. FIG. 1 is a block diagram showing a schematic configuration of a power unit to which the torque converter 1 is applied. FIG. 2 is a diagram showing the overall structure of the torque converter 1. FIG. 3 is an enlarged perspective view showing the front boss 10 of the torque converter 1.

  As shown in FIG. 1, a continuously variable output shaft (crankshaft) 3a of the engine 3 converts a driving force from the engine 3 and outputs the same through a torque converter 1 having a clutch function and a torque amplification function. The transmission 5 is connected. Here, as the engine 3, for example, an engine with a 180-degree crank, that is, an engine in which combustion strokes occur at 180-degree intervals, is preferably used. For example, as the engine 3, a horizontally opposed four cylinder engine or the like is preferably used.

  The torque converter 1 mainly includes a pump impeller 11, a turbine runner 12, and a stator 13. The pump impeller 11 connected to the output shaft (crankshaft) 3a of the engine 3 produces a flow of oil, and the turbine runner 12 arranged facing the pump impeller 11 receives the driving force of the engine 3 via the oil. The turbine output shaft 23 is driven. The stator 13 located between the two rectifies the exhaust flow (return) from the turbine runner 12 and returns it to the pump impeller 11 to generate a torque amplification action.

  Particularly, in the torque converter 1 according to the present embodiment, the stress acting on the base end portion (root) of the front boss 10 due to the displacement of the crankshaft 3a can be reduced, and the base end portion of the front boss 10 serves as a starting point. It has the function of preventing the occurrence of cracks (fatigue fracture). Hereinafter, it will be described in more detail with reference to FIG.

  The crankshaft 3a (only a part of which is shown in FIG. 2) of the engine 3 converts the reciprocating motion of the piston into a rotary motion via the connecting rod. The crankshafts 3a are arranged in a straight line with a space therebetween, and are located between a crank journal (main journal) supported by a cylinder block via a main metal and adjacent crank journals, and a large end portion of the connecting rod. And a crank pin to which is attached.

An output flange (large diameter portion) 3c is provided at the rear end of the crankshaft 3a. A fitting hole (recess) 3b into which the front boss 10 of the torque converter 1 is fitted is formed in the center of the output flange 3c.

  A front cover 21 is connected to an output flange 3c formed at the end of the crankshaft 3a via a disc member 20. A pump impeller (impeller shell) 11 having a plurality of blades 11 a is connected (fixed) to an end portion of the front cover 21.

  A front boss (pilot boss) 10 formed in a substantially columnar shape is provided at the center of the front cover 21. When the crankshaft 3a of the engine 3 and the torque converter 1 are fastened, the front boss 10 provided at the center of the front cover 21 is fitted into the fitting hole 3b formed at the center of the rotation axis of the end surface of the crankshaft 3a. Axial alignment (position alignment) is performed by aligning.

  The substantially cylindrical front boss 10 is formed with a notch 10a extending from the top surface to the side surface and having a predetermined depth in the axial direction of the front boss 10. The notch 10a is formed, for example, in a straight line shape (slit shape) having a predetermined width in the radial direction, passing through the axial center of the front boss 10 when viewed from the axial direction of the front boss 10 (in plan view). There is. Further, when viewed from the side surface direction of the front boss 10 (in a side view), it is formed in a substantially U-shaped katakana. In particular, the notch 10a easily bends with respect to an input load and effectively disperses the stress caused by the displacement of the crankshaft 3a. Therefore, the notch 10a is in a direction substantially orthogonal to the reciprocating direction of the piston of the engine 3 to be coupled. It is preferably formed so as to extend along.

  Further, even if a crack is formed, the cutout 10a has a depth in the axial direction from the corner of the bottom of the cutout 10a as a starting point from the viewpoint of preventing oil leakage from the torque converter 1. Even if it is assumed that the crack extends at an angle of 45 degrees with the axis of 10, the crack is preferably formed at a depth that does not connect to the inside of the torque converter 1 (that is, oil does not leak). For example, the notch 10a has an axial depth substantially the same as the depth at which the side surface of the fitting hole 3b formed in the crankshaft 3a of the engine 3 to be coupled and the side surface of the front boss 10 contact. Alternatively, it is preferably formed to be slightly deeper than that (that is, the same as or slightly deeper than the contacting cylindrical surface with the crankshaft 3a).

  Further, from the viewpoint of achieving a good balance between the strength of the front boss 10 and the flexibility (flexibility), the width of the notch 10a (the above-mentioned predetermined width) is 1/2 or more and ¼ of the diameter of the front boss 10. The following settings are preferable. In particular, the width of the notch 10a (the predetermined width) is more preferably set to approximately 1/3 of the diameter of the front boss 10.

  Further, from the viewpoint of concentrating the stress caused by the displacement of the crankshaft 3a on the side of the notch 10a, the corner portion at the bottom of the notch 10a may not be R-chamfered (that is, R is not attached). preferable. On the other hand, the base end portion (root) of the front boss 10 is chamfered along the circumferential direction so as to be larger than the corner portion of the bottom portion of the notch 10a (that is, a larger R is provided. ) Is preferred.

  A torque converter sleeve 15 is joined by welding or the like to the inner peripheral side of the pump impeller (impeller shell) 11 described above.

  A turbine runner 12 including a plurality of blades 12a is rotatably housed in a converter chamber 30 defined by the front cover 21 and the pump impeller 11. The turbine runner 12 is arranged so as to face the pump impeller 11. A turbine hub 22 is fixed to the turbine runner 12, and a turbine output shaft 23 is spline-coupled to the turbine hub 22. Further, a stator 13 having a plurality of blades 13 a is provided between the pump impeller 11 and the turbine runner 12 facing each other. The stator 13 is attached to the mission case 5b via a one-way clutch 14.

  A lockup piston 31 is arranged between the front cover 21 and the turbine runner 12 so as to face the inner surface of the front cover 21. The lock-up piston 31 is axially movable and attached to the turbine hub 22. An annular lockup clutch 32 is attached to the outer edge of the surface of the lockup piston 31 facing the front cover 21.

  The lock-up piston 31 partitions the converter chamber 30 into a release chamber 34 on the front cover 21 side and an apply chamber 33 on the turbine runner 12 side. That is, the release chamber 34 is defined by the front cover 21 and the lockup piston 31, and the apply chamber 33 is formed (defined) so as to face the release chamber 34 across the lockup piston 31. Depending on the pressure difference between the apply chamber 33 and the release chamber 34, the lock-up piston 31 moves in the engaging direction (direction toward the front cover 21) or the releasing direction (direction away from the front cover 21) of the lock-up clutch 32. Move back and forth.

  Further, a damper mechanism 41 including a plurality of damper springs 42 and a holding member 43 that holds the damper springs 42 is attached between the lockup piston 31 and the turbine hub 22. More specifically, one end of each damper spring 42 is attached to the lockup piston 22, and the other end is attached to the turbine hub 22 via the holding member 43. The damper mechanism 41 absorbs torque fluctuation (shock) when the lockup clutch 32 is engaged (lockup).

  The torque converter sleeve 15 described above has a tubular portion that extends in the axial direction and a flange that extends in the radial direction from one end of the tubular portion. This flange has an outer diameter that matches the inner diameter surface of the central hole of the pump impeller (impeller shell) 11. The turbine output shaft 23 described above is inserted through the center of the rotation shaft of the torque converter sleeve 15. The turbine output shaft 23 (output shaft of the torque converter 1) is connected (coupled) to the input shaft 5a of the continuously variable transmission 5.

  Between the torque converter sleeve 15 and the transmission case 5b, a bearing 17 that rotatably supports the torque converter sleeve 15 and receives an axial (thrust direction) hydraulic load acting on the inner diameter surface of the torque converter 1. It is installed. As the bearing 17, a rolling bearing (for example, a ball bearing) is preferably used.

  With the above configuration, after the torque converter 1 is assembled to the crankshaft 3a of the engine 3, the engine 3 is driven and the displacement of the crankshaft 3a due to the engine operation is input to the front boss 10 as a load. In this case, the stress caused by the input load due to the displacement of the crankshaft 3a is distributed to the base end portion (root) of the front boss 10 and the bottom portion of the notch 10a. Then, since the generated stress is dispersed, the stress at the base end portion (root) of the front boss 10 is reduced, and the fatigue breakage of the front boss 10 is prevented.

  As described above in detail, according to the present embodiment, since the notch 10a is formed from the top surface to both side surfaces of the front boss 10 formed in a substantially columnar shape, the input due to the displacement of the crankshaft 3a is performed. The stress caused by the load can be dispersed to the base end portion (root) of the front boss 10 and the bottom portion of the notch 10a. By dispersing the generated stress, the stress at the base end portion of the front boss 10 is reduced, and the fatigue damage of the front boss 10 is prevented. As a result, the stress acting on the base end (root) of the front boss 10 due to the displacement of the crankshaft 3a can be reduced, and the occurrence of cracks (fatigue fracture) originating from the base end of the front boss 10 can be prevented. It becomes possible to do.

  According to the present embodiment, the notch 10a is formed in a straight line that passes through the axial center and has a predetermined width in the radial direction when viewed in the axial direction of the front boss 10. It is possible to effectively disperse the resulting stress.

  Further, according to the present embodiment, the notch 10a is formed so as to extend along a direction substantially orthogonal to the reciprocating direction of the piston of the engine 3 to be coupled, so that it is caused by the displacement of the crankshaft 3a. It becomes easy to bend with respect to the applied stress, and it becomes possible to disperse the stress more effectively.

  According to this embodiment, the axial depth of the notch 10a is substantially the same as the depth at which the side surface of the fitting hole 3b formed in the crankshaft 3a of the engine 3 to be joined and the side surface of the front boss 10 are in contact. Since it is formed at a depth or slightly deeper than that (that is, the same as or slightly deeper than the contact cylindrical surface with the crankshaft 3a), the stress caused by the displacement of the crankshaft 3a can be effectively applied. It becomes possible to disperse.

  Further, according to the present embodiment, even if it is assumed that the axial depth of the notch 10a has a corner extending from the corner of the bottom of the notch 10a as an origin, the crack extends at an angle of 45 degrees with the axis, Since the crack is formed to a depth that does not connect to the inside of the torque converter 1, even if a crack is formed, it is possible to prevent oil leakage from the torque converter 1.

  According to the present embodiment, since the width of the notch 10a is set to approximately 1/3 of the diameter of the front boss 10, the strength and the flexibility (flexibility) can be balanced in a good balance. It is possible to more effectively disperse the stress caused by the displacement of the crankshaft 3a.

  According to the present embodiment, since no R is attached to the bottom corner of the cutout 10a, the stress is concentrated on the cutout 10a of the front boss 10 instead of the base end (root) of the front boss 10 ( That is, the fuse function is exerted).

  Further, according to the present embodiment, the base end portion (root) of the front boss 10 is provided with a larger radius R than the corner portion of the bottom portion of the notch 10a along the circumferential direction, so that the crankshaft 3a has It is possible to concentrate the stress caused by the displacement on the notch 10a side.

  According to this embodiment, the front boss 10 is fitted into the fitting hole 3b formed in the crankshaft 3a of the engine 3 having a 180-degree crank (the engine 3 having a combustion stroke at 180-degree intervals), that is, By connecting the torque converter 1 to the engine 3 having a 180-degree crank, the stress caused by the displacement of the crankshaft 3a can be more effectively dispersed.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and various modifications can be made. For example, the extending direction, width, depth, shape, number, arrangement, etc. of the cutouts 10a are not limited to those in the above embodiment, and can be set arbitrarily according to, for example, required requirements. For example, the notch 10a may be formed in a cross shape or a V shape when viewed in the axial direction.

  Further, in the above embodiment, the case where the torque converter 1 is coupled to the engine 3 having a 180-degree crank (the engine 3 having combustion strokes at 180-degree intervals) has been described as an example, but the present invention is not limited to the 180-degree crank. It can also be applied to a torque converter coupled with an engine.

  Similarly, in the above embodiment, the case where the present invention is combined with the continuously variable transmission (CVT) 5 has been described as an example, but the present invention may be combined with, for example, a stepped automatic transmission (step AT). You can also

1 Torque Converter 3 Engine 3a Crankshaft 3b Fitting Hole 5 Continuously Variable Transmission 10 Front Boss (Pilot Boss)
10a Notch 11 Pump impeller 12 Turbine runner 13 Stator 20 Disk member 21 Front cover 22 Turbine hub 23 Turbine output shaft 31 Lock-up piston 32 Lock-up clutch 33 Apply chamber 34 Release chamber 41 Damper mechanism 42 Damper spring 43 Holding member

Claims (9)

It is formed in a substantially columnar shape and has a front boss protruding from the center of the front cover.
The torque converter characterized in that the front boss is formed with a notch having a predetermined depth in the axial direction from the top surface to the side surface.   The torque converter according to claim 1, wherein the notch is formed in a straight line that passes through the axial center and has a predetermined width in the radial direction when viewed from the axial direction of the front boss.   The torque converter according to claim 2, wherein the notch is formed so as to extend along a direction substantially orthogonal to a reciprocating direction of a piston of an engine to be coupled.   The notch is formed so that an axial depth thereof is substantially the same as a depth at which a fitting hole formed in a crankshaft of an engine to be coupled and a front boss are in contact with each other. The torque converter according to any one of 1 to 3.   Even if it is assumed that the notch has an axial depth of 45 degrees from the corner of the bottom of the notch as the starting point, the crack extends inside the torque converter. The torque converter according to any one of claims 1 to 4, wherein the torque converter is formed to a depth that does not connect.   The torque converter according to claim 2, wherein the predetermined width is set to approximately 1/3 of a diameter of the front boss.   The torque converter according to any one of claims 1 to 6, wherein a corner portion of a bottom portion of the notch is not chamfered.   8. The front boss is provided with a rounded chamfer at a base end portion along a circumferential direction, which is larger than a corner portion of a bottom portion of the cutout, according to any one of claims 1 to 7. The described torque converter. The said front boss is fitted in the fitting hole formed in the crankshaft of the engine of a 180 degree crank, when it couple | bonds with an engine, The claim | item 1 characterized by the above-mentioned. Torque converter.

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