JP2022047435A - Rotor fixing device for vehicle - Google Patents

Abstract

To provide a rotor fixing device for a vehicle capable of suppressing degrading of fatigue strength in a low strength part.SOLUTION: A base end section 46a of a secondary piston 46 includes a low strength section 46j which adjoins a spline fitting section 52a and has lower strength. A crowning protrusion section 38h is formed so that a thickest section 38i where a teeth thickness t of outer periphery spline tooth 38c is maximum is arranged opposite to the low strength section 46j with respect to a center position in a rotation axis C direction of the outer periphery spline tooth 38c. Accordingly, the thickest section 38i of the crowning protrusion section 38h is favorably separated from the low strength section 46j, therefore a stress generated by press fitting a tooth face 38g and 46g of the outer periphery spline tooth 38c of a secondary shaft 38 and a second inner periphery spline tooth 46i of the secondary piston 46 is favorably prevented from concentrating the low strength section 46j.SELECTED DRAWING: Figure 3

Description

In the present invention, the first rotating body and the second rotating body are fixed to each other by press-fitting the tooth surfaces of the spline teeth formed on the first rotating body and the spline teeth formed on the second rotating body. The present invention relates to a rotating body fixing device for a vehicle, and relates to a technique for suppressing a decrease in fatigue strength in a low-strength portion formed on the other of the first rotating body and the second rotating body.

The spline teeth formed on the first rotating body and the spline teeth formed on the second rotating body have tooth surfaces formed along the common rotation axis direction between the first rotating body and the second rotating body. A well-known device for fixing a rotating body for a vehicle is one in which the first rotating body and the second rotating body are mutually fixed by a spline fitting portion fitted by press-fitting each other. For example, it is the rotating body fixing device for a vehicle described in Patent Document 1. In Patent Document 1, a crowning convex portion that bulges in the circumferential direction of the first rotating body or the second rotating body on the tooth surface of one of the spline teeth of the first rotating body and the second rotating body. By forming the spline fitting portion, the tooth surface formed along the rotation axis direction while eliminating the play between the spline teeth of the first rotating body and the spline teeth of the second rotating body. It is described that the tooth surface press-fitting work of press-fitting each other is facilitated.

Japanese Unexamined Patent Publication No. 7-083242

By the way, on the other side of the first rotating body and the second rotating body, for example, a through hole in the radial direction and a notch groove in the circumferential direction are formed adjacent to the spline fitting portion to reduce the strength. There may be a part. When the low-strength portion is present on the other side of the first rotating body and the second rotating body, the tooth surfaces of the spline teeth of the first rotating body and the spline teeth of the second rotating body are press-fitted together. As a result, there is a risk that the stress generated will be concentrated on the low-strength portion and the fatigue strength in the low-strength portion will decrease.

The present invention has been made in the background of the above circumstances, and an object of the present invention is to provide a rotating body fixing device for a vehicle capable of suppressing a decrease in fatigue strength in a low-strength portion. ..

The gist of the first invention is that (a) the spline teeth formed on the first rotating body and the spline teeth formed on the second rotating body are the first rotating body and the second rotating body. The first rotating body and the second rotating body are mutually fixed by a spline fitting portion fitted by press-fitting tooth surfaces formed along a common rotation axis direction, and the first rotating body is fixed to each other. A rotating body fixing device for vehicles in which a crowning protrusion that bulges in the circumferential direction of the first rotating body or the second rotating body is formed on the tooth surface of one spline tooth of the rotating body and the second rotating body. (B) The other of the first rotating body and the second rotating body has a low-strength portion adjacent to the spline fitting portion and having a reduced strength, and (c) the crowning. The convex portion is formed so that the thickest portion having the maximum tooth thickness of the spline tooth is arranged on the side opposite to the low strength portion with respect to the central position of the one spline tooth in the direction of the rotation axis. It is in the fact that it is.

According to the rotating body fixing device for a vehicle of the first invention, (b) the other of the first rotating body and the second rotating body has a low-strength portion having a reduced strength adjacent to the spline fitting portion. (C) The crowning convex portion has the thickest portion having the maximum tooth thickness of the spline tooth, which is the low strength portion with respect to the central position of the one spline tooth in the direction of the rotation axis. It is formed so as to be arranged on the opposite side. Therefore, since the thickest portion of the crowning convex portion is suitably separated from the low-strength portion, the tooth surfaces of the spline teeth of the first rotating body and the spline teeth of the second rotating body are press-fitted together. It is preferably suppressed that the stress generated thereby is concentrated on the low-strength portion. This makes it possible to suppress a decrease in fatigue strength in the low-strength portion.

Here, preferably, the low-strength portion is formed in the hole or other portion where the notch groove is not formed by the hole or notch groove formed in the other of the first rotating body and the second rotating body. In comparison, it is a portion where the strength of the other part of the first rotating body and the second rotating body is lowered. Therefore, it is possible to suitably suppress a decrease in fatigue strength of the low-strength portion in which the hole and the notch groove are formed.

It is a skeleton diagram explaining the schematic structure of the drive device for a vehicle to which this invention is applied. It is sectional drawing explaining the structure of the secondary shaft and the secondary piston. FIG. 2 is a sectional view taken along line III-III of FIG. 2, showing a state in which the tooth surfaces of the outer peripheral spline teeth formed on the secondary shaft and the second inner peripheral spline teeth formed on the secondary piston are press-fitted together. It is sectional drawing which shows the secondary piston and the secondary shaft before the tooth surface of the inner peripheral spline tooth formed in the secondary piston is press-fitted into the tooth surface of the outer peripheral spline tooth formed in the secondary shaft. FIG. 4 is a sectional view taken along line VV of FIG. 4, showing a state before the tooth surfaces of the outer peripheral spline teeth formed on the secondary shaft and the inner peripheral spline teeth formed on the secondary piston are press-fitted together. It is sectional drawing which shows the spline fitting part of the rotating body fixing device of the comparative example different from the rotating body fixing device of this Example.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following examples, the drawings are appropriately simplified or modified, and the dimensional ratios and shapes of each part are not always drawn accurately.

FIG. 1 is a skeleton diagram illustrating a schematic configuration of a vehicle drive device 10 (hereinafter referred to as a drive device 10) to which the present invention is applied. As shown in FIG. 1, the drive device 10 can transmit power to the engine 12 via, for example, an engine 12 used as a driving force source for traveling, a torque converter 14 as a fluid transmission device, and a torque converter 14. An output shaft 28 having a connected input shaft 16, a forward / backward switching device 18, a belt-type stepless transmission 20, a gear mechanism 22, and an output gear 26 connected to the drive wheels 24 so as to be able to transmit power. And a differential gear device 30. In the drive device 10, a belt-type continuously variable transmission 20 and a gear mechanism 22 are provided in parallel between the input shaft 16 and the output shaft 28. In the drive device 10 configured in this way, the first transmission path P1 in which the driving force output from the engine 12 is transmitted from the input shaft 16 to the output shaft 28 via the belt type continuously variable transmission 20 and the engine 12 A second transmission path P2 in which the driving force output from the input shaft 16 is transmitted from the input shaft 16 to the output shaft 28 via the gear mechanism 22 is formed.

As shown in FIG. 1, the belt-type continuously variable transmission 20 is wound between the primary pulley 32 having a variable effective diameter, the secondary pulley 34 having a variable effective diameter, and the primary pulley 32 and the secondary pulley 34. It is equipped with a transmission belt 36. As shown in FIG. 1, the secondary pulley 34 is relative to the secondary shaft 38 rotatably supported around the rotation axis C, the fixed sheave 40 integrally fixed to the secondary shaft 38, and the secondary shaft 38. A movable sheave 42 that is non-rotatable and is provided so as to be movable in the rotation axis C direction with respect to the secondary shaft 38, and a movable sheave 42 for changing the V-groove width between the fixed sheave 40 and the movable sheave 42. It includes a hydraulic actuator 44 that generates a thrust for moving in the C direction. The secondary shaft 38 is a rotating body (first rotating body) that rotates around the rotation axis C.

As shown in FIG. 2, the hydraulic actuator 44 has a secondary piston 46 integrally fixed to the secondary shaft 38, an oil chamber 48 formed between the secondary piston 46 and the movable sheave 42, and a movable sheave 42. A coil spring 50 for urging the fixed sheave 40 side is provided. In the hydraulic actuator 44, the secondary pressure Pout output from the solenoid valve provided in the hydraulic control circuit (not shown) is formed in, for example, the first axial oil passage 38a formed in the secondary shaft 38 and the movable sheave 42. It is supplied into the oil chamber 48 via the oil passage 42a or the like. Further, the movable sheave 42 and the secondary shaft 38 are spline-fitted. Further, FIG. 2 is a cross-sectional view illustrating the configuration of the secondary shaft 38 and the secondary piston 46.

As shown in FIG. 2, the secondary piston 46 integrally includes a base end portion 46a, a drum portion 46b, and a connecting portion 46c. The base end portion 46a is a cylindrical member arranged on the tip end portion 38b of the secondary shaft 38. Further, the drum portion 46b functions as a clutch drum of the belt traveling clutch C1 (see FIG. 1) that selectively engages the secondary piston 46, that is, the secondary shaft 38 and the output shaft 28. Further, the connecting portion 46c connects the base end portion 46a and the drum portion 46b. The secondary piston 46 is a rotating body (second rotating body) that rotates around the rotation axis C common to the secondary shaft 38.

As shown in FIG. 2, a plurality of inner peripheral spline teeth 46d extending in the rotation axis C direction, a first oil hole (hole) 46e, and a second oil hole 46f are formed on the base end portion 46a of the secondary piston 46. , Are formed. As shown in FIG. 3, the tooth surfaces 46g of the plurality of inner peripheral spline teeth 46d are each formed along the rotation axis C direction. Further, the plurality of inner peripheral spline teeth 46d are formed at equal intervals in the circumferential direction of the secondary piston 46, respectively. Further, in a part of the inner peripheral spline tooth 46d, as shown in FIGS. 2 and 3, the inner peripheral spline tooth 46d is formed by the radial first oil hole 46e penetrating the proximal end portion 46a of the secondary piston 46. There is a part that is not. In the inner peripheral spline tooth 46d, the inner peripheral spline tooth 46d on the movable sheave 42 side with respect to the first oil hole 46e is set as the first inner peripheral spline tooth 46h, which is opposite to the movable sheave 42 side with respect to the first oil hole 46e. The inner peripheral spline tooth 46d on the side is referred to as a second inner peripheral spline tooth (spline tooth) 46i. Further, as shown in FIG. 2, the first oil hole 46e is formed in the tip portion 38b of the secondary shaft 38 via the first radial oil passage 38d that penetrates the tip portion 38b of the secondary shaft 38 in the radial direction. It is an oil hole that communicates with the second axial oil passage 38e. Further, as shown in FIG. 2, the second oil hole 46f communicates with the second axial oil passage 38e via the second radial oil passage 38f penetrating the tip portion 38b of the secondary shaft 38 in the radial direction. It is a hole. FIG. 3 is a sectional view taken along line III-III of FIG. 2, which is formed on the outer peripheral spline teeth (spline teeth) 38c formed on the tip portion 38b of the secondary shaft 38 and the base end portion 46a of the secondary piston 46. It is a figure which shows the state which the tooth surface 38g and 46g with the 2nd inner peripheral spline tooth 46i are press-fitted together.

As shown in FIGS. 2 and 3, a plurality of outer peripheral spline teeth 38c extending in the rotation axis C direction are formed on the tip end portion 38b of the secondary shaft 38. As shown in FIG. 3, the tooth surfaces 38g of the plurality of outer peripheral spline teeth 38c are each formed along the rotation axis C direction. Further, the plurality of outer peripheral spline teeth 38c are formed at equal intervals in the circumferential direction of the secondary shaft 38, respectively.

As shown in FIG. 2, a rotating body fixing device (rotating body for a vehicle) for fixing the secondary shaft 38 and the secondary piston 46 to each other between the tip portion 38b of the secondary shaft 38 and the base end portion 46a of the secondary piston 46. A fixing device) 52 is provided. In the rotating body fixing device 52, as shown in FIG. 3, the outer peripheral spline teeth 38c and the second inner peripheral spline teeth 46i are fitted (spline fitting) by press-fitting the tooth surfaces 38g and 46g together. The secondary shaft 38 and the secondary piston 46 are fixed to each other by the spline fitting portion 52a.

As shown in FIG. 2, the base end portion 46a of the secondary piston 46 is an annular low-strength portion in which the strength of the base end portion 46a of the secondary piston 46 is lower than that of other portions adjacent to the spline fitting portion 52a. It has 46j. The low-strength portion 46j includes a first oil hole 46e formed adjacent to the spline fitting portion 52a at the base end portion 46a of the secondary piston 46 and an annular notched groove cut out in the circumferential direction of the secondary piston 46. This is a portion where the strength of a part of the base end portion 46a of the secondary piston 46 is lower than that of the other portion where the first oil hole 46e and the notch groove 46k are not formed by the 46k.

As shown in FIG. 5, a crowning convex portion 38h that bulges in the circumferential direction of the secondary shaft 38 is formed on the tooth surface 38g of the outer peripheral spline tooth 38c formed on the tip portion 38b of the secondary shaft 38. Since the crowning convex portion 38h is formed on the tooth surface 38g of the outer peripheral spline tooth 38c, the tooth thickness t [mm] of the outer peripheral spline tooth 38c in the circumferential direction of the secondary shaft 38 is directed toward both ends of the outer peripheral spline tooth 38c. It is gradually decreasing. Further, as shown in FIG. 5, the crowning convex portion 38h has a distance S [mm] between the tooth thickness tmin [mm] at both ends of the outer peripheral spline tooth 38c and the inner peripheral spline tooth 46d facing the circumferential direction of the secondary piston 46. ], And is formed on the tooth surface 38g of the outer peripheral spline tooth 38c so that the tooth thickness tmax [mm] of the thickest portion 38i of the outer peripheral spline tooth 38c is larger than the interval S [mm]. The thickest portion 38i of the outer peripheral spline tooth 38c is a portion where the tooth thickness t of the outer peripheral spline tooth 38c is maximum. Further, in the plurality of outer peripheral spline teeth 38c, as shown in FIG. 3, the crowning convex portion 38h has the thickest portion 38i having the maximum tooth thickness t of the outer peripheral spline teeth 38c in the rotation axis C direction of the outer peripheral spline teeth 38c. It is formed so as to be arranged on the side opposite to the low-strength portion 46j with respect to the central position, that is, on the side away from the low-strength portion 46j. That is, in the plurality of outer peripheral spline teeth 38c, as shown in FIG. 3, the distance between the thickest portion 38i and the low-strength portion 46j is the central position of the crowning convex portion 38h in the rotation axis C direction of the outer peripheral spline teeth 38c. It is formed so as to be longer than the distance between the low-strength portion 46i and the low-strength portion 46i. The alternate long and short dash line L1 shown in FIG. 3 is a line indicating the position of the thickest portion 38i of the plurality of outer peripheral spline teeth 38c, and the alternate long and short dash line L2 shown in FIG. 3 is the plurality of outer peripheral spline teeth. It is a line which shows the central position in the rotation axis C direction of 38c. Further, FIG. 4 shows the secondary piston 46 and the secondary shaft before the tooth surface 46g of the inner peripheral spline tooth 46d formed on the secondary piston 46 is press-fitted into the tooth surface 38g of the outer peripheral spline tooth 38c formed on the secondary shaft 38. It is sectional drawing which shows 38. Further, FIG. 5 is a cross-sectional view taken along the line VV of FIG. 4, showing the tooth surfaces 46g and 38g of the inner peripheral spline teeth 46d formed on the secondary piston 46 and the outer peripheral spline teeth 38c formed on the secondary shaft 38. It is a figure which shows the state before press-fitting.

Here, a tooth surface press-fitting operation of press-fitting the tooth surfaces 38g and 46g of the outer peripheral spline teeth 38c formed on the secondary shaft 38 and the second inner peripheral spline teeth 46i formed on the secondary piston 46 will be described. First, as shown in FIGS. 4 and 5, the first inner peripheral spline tooth 46h of the secondary piston 46 is fitted into the end of the outer peripheral spline tooth 38c of the secondary shaft 38. Next, the secondary piston 46 is moved in the direction approaching the movable sheave 42, that is, in the direction of the arrow F shown in FIG. 4, until the base end portion 46a of the secondary piston 46 abuts on the stopper portion 38j formed on the secondary shaft 38. As a result, as shown in FIG. 3, the tooth surfaces 38g and 46g of the outer peripheral spline teeth 38c of the secondary shaft 38 and the second inner peripheral spline teeth 46i of the secondary piston 46 are press-fitted together. After the tooth surfaces 38g and 46g of the outer peripheral spline tooth 38c and the second inner peripheral spline tooth 46i are press-fitted together, the fastening nut 54 is screwed to the secondary shaft 38 as shown in FIG. 2, and the secondary piston 46 Is unable to move in the direction of the rotation axis C with respect to the secondary shaft 38. The fastening nut 54 is provided with a rotation prevention portion 54a that prevents the fastening nut 54 from rotating by being plastically deformed. Further, in a state where the tooth surfaces 38g and 46g of the outer peripheral spline tooth 38c and the second inner peripheral spline tooth 46i are press-fitted together, as shown in FIG. 3, the tooth in the peripheral portion of the thickest portion 38i of the outer peripheral spline tooth 38c. The surface 38g is only in contact with the tooth surface 46g of the second inner peripheral spline tooth 46i, but the driving force output from the engine 12 is transmitted to the output shaft 28 via the belt type stepless transmission 20. When the torque T (see FIG. 3) is transmitted from the secondary shaft 38 to the secondary piston 46, the outer circumference is such that the entire surface of the tooth surface 38g of the outer peripheral spline tooth 38c comes into contact with the tooth surface 46g of the second inner peripheral spline tooth 46i. The spline tooth 38c and the second inner peripheral spline tooth 46i are elastically deformed.

FIG. 6 is a cross-sectional view showing a spline fitting portion 52b of a rotating body fixing device of a comparative example different from the rotating body fixing device 52 of the present embodiment. In the rotating body fixing device of the comparative example, the crowning convex portion 38l is the tooth of the outer peripheral spline tooth 38c so that the thickest portion 38k of the outer peripheral spline tooth 38c is at the center position in the rotation axis C direction of the outer peripheral spline tooth 38c. The difference is that it is formed on the surface 38 g, and other than that, it is substantially the same as the rotating body fixing device 52 of this embodiment. As shown in FIGS. 3 and 6, in the rotating body fixing device 52 of the present embodiment and the rotating body fixing device of the comparative example, the tooth surface 38g of the outer peripheral spline tooth 38c and the second inner peripheral spline tooth 46i, In a state where 46 g are press-fitted together, the thickest portion 38i of the outer peripheral spline teeth 38c of this embodiment is separated from the lower strength portion 46j than the thickest portion 38k of the outer peripheral spline teeth 38c of the comparative example. Therefore, in the rotating body fixing device 52 of the present embodiment, the stress generated by press-fitting the tooth surfaces 38g and 46g of the outer peripheral spline tooth 38c and the second inner peripheral spline tooth 46i is the rotation of the comparative example. It is farther from the low-strength portion 46j than the body fixing device.

As described above, according to the rotating body fixing device 52 of the present embodiment, the base end portion 46a of the secondary piston 46 has a low-strength portion 46j adjacent to the spline fitting portion 52a and having a reduced strength. In the crowning convex portion 38h, the thickest portion 38i having the maximum tooth thickness t of the outer peripheral spline tooth 38c is arranged on the side opposite to the low strength portion 46j with respect to the central position of the outer peripheral spline tooth 38c in the rotation axis C direction. It is formed to be. Therefore, since the thickest portion 38i of the crowning convex portion 38h is suitably separated from the low-strength portion 46j, the tooth surface 38g between the outer peripheral spline teeth 38c of the secondary shaft 38 and the second inner peripheral spline teeth 46i of the secondary piston 46. It is preferably suppressed that the stress generated by press-fitting the 46 g to each other is concentrated on the low-strength portion 46j. As a result, it is possible to suppress a decrease in fatigue strength in the low-strength portion 46j.

Further, according to the rotating body fixing device 52 of the present embodiment, the low-strength portion 46j has the first oil hole 46e and the notch due to the first oil hole 46e and the notch groove 46k formed in the base end portion 46a of the secondary piston 46. This is a portion where the strength of a part of the base end portion 46a of the secondary piston 46 is lower than that of the other portion where the groove 46k is not formed. Therefore, it is possible to suitably suppress a decrease in fatigue strength of the low-strength portion 46j in which the first oil hole 46e and the notch groove 46k are formed.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the present invention is also applicable to other aspects.

For example, in the above-mentioned Example 1, the crowning convex portion 38h is formed on the tooth surface 38g of the outer peripheral spline tooth 38c of the secondary shaft 38 which is one of the secondary shaft 38 and the secondary piston 46. For example, the outer peripheral spline tooth 38c is formed. A crowning convex portion that bulges in the circumferential direction of the secondary piston 46 may be formed on the tooth surface 46g of the second inner peripheral spline tooth 46i of the secondary piston 46 without forming the crowning convex portion 38h on the tooth surface 38g of the secondary piston 46. .. When a crowning convex portion is formed on the tooth surface 46g of the second inner peripheral spline tooth 46i, the first diameter is formed by the first radial oil passage 38d, which is a hole formed in the tip portion 38b of the secondary shaft 38. A portion where the strength of a part of the tip portion 38b of the secondary shaft 38 is lower than that of the portion where the directional oil passage 38d is not formed becomes a low-strength portion. Further, in the crowning convex portion formed on the tooth surface 46g of the second inner peripheral spline tooth 46i, the thickest portion where the tooth thickness of the second inner peripheral spline tooth 46i is maximum is the rotation axis of the second inner peripheral spline tooth 46i. It is formed so as to be arranged on the side opposite to the low-strength portion where the first radial oil passage 38d is formed with respect to the central position in the C direction. In the rotating body fixing device 52 configured as described above, the thickest portion of the crowning convex portion formed on the tooth surface 46g of the second inner peripheral spline tooth 46i has a low strength in which the first radial oil passage 38d is formed. Since it is suitably separated from the portion, the stress generated by press-fitting the tooth surfaces 38g and 46g of the outer peripheral spline teeth 38c of the secondary shaft 38 and the second inner peripheral spline teeth 46i of the secondary piston 46 into the first radial direction. Concentration on the low-strength portion where the oil passage 38d is formed is preferably suppressed.

Further, in the above-mentioned Example 1, the first oil hole 46e and the notch groove 46k are formed in the low-strength portion 46j, respectively, but the first oil hole 46e and the notch groove 46k are not necessarily formed in the low-strength portion 46j, respectively. It does not have to be formed. For example, only one of the first oil hole 46e and the notch groove 46k may be formed.

It should be noted that the above is only one embodiment, and the present invention can be carried out in a mode in which various changes and improvements are made based on the knowledge of those skilled in the art.

38: Secondary shaft (first rotating body)
38c: Outer peripheral spline teeth (spline teeth)
38g: Tooth surface 38h: Crowning convex portion 38i: Thickest portion 46: Secondary piston (second rotating body)
46g: Tooth surface 46i: Second inner peripheral spline tooth (spline tooth)
46j: Low-strength portion 52: Rotating body fixing device (rotating body fixing device for vehicles)
52a: Spline fitting portion C: Rotation axis t: Tooth thickness

Claims (1)

The spline teeth formed on the first rotating body and the spline teeth formed on the second rotating body have tooth surfaces formed along the common rotation axis direction between the first rotating body and the second rotating body. The first rotating body and the second rotating body are fixed to each other by the spline fitting portion fitted by press-fitting each other, and one spline tooth of the first rotating body and the second rotating body is fixed to each other. A rotating body fixing device for a vehicle, wherein a crowning convex portion that bulges in the circumferential direction of the first rotating body or the second rotating body is formed on the tooth surface of the above.
The other of the first rotating body and the second rotating body has a low-strength portion having a low strength adjacent to the spline fitting portion.
The crowning convex portion is arranged so that the thickest portion having the maximum tooth thickness of the spline tooth is arranged on the side opposite to the low strength portion with respect to the central position of the one spline tooth in the direction of the rotation axis. A rotating body fixing device for a vehicle, characterized in that it is formed.

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