JPH08261194A - Drive shaft device - Google Patents

Abstract

PURPOSE: To provide a drive shaft device without worsening durability of a bearing. CONSTITUTION: A drive shaft 4 is bearing-supported on a housing 1 rotatably through a bearing 6. In a drive shaft device of mounting a pulley 13 in a protruding end 4a from the housing 1 of the drive shaft 4 to drive it rotated by this pulley 13, a flexible part 19 of low rigidity is provided in the drive shaft 4 to be positioned between the bearing 6 and the pulley 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive shaft device suitable for application to a cooling water circulating water pump of an internal combustion engine.

[0002]

2. Description of the Related Art A drive shaft device of this type has a drive shaft rotatably supported by a housing via a bearing and a pulley attached to a projecting end of the drive shaft from the housing. In the water pump, the pump impeller attached to the drive shaft is rotationally driven by rotationally driving the drive shaft. In addition, similar technology,
It is disclosed in Japanese Utility Model Laid-Open No. 59-79519.

[0003]

In the above-mentioned conventional example, the belt is wound around the pulley, and the belt rotationally drives the pulley with a predetermined tension. When the tension of the belt acts on the drive shaft, the drive shaft is mechanically supported by the housing through a bearing that uses rollers or balls as rolling elements, so the drive shaft is mechanically cantilevered with the bearing portion as the fixed end. It becomes a beam and a bending moment acts on the drive shaft. If the bending stiffness of the drive shaft is constant, the maximum bending moment acts on the bearing portion, and as a result, the contact surface pressure of the bearing increases, which may impair the durability of the bearing.

The present invention has been devised in view of such conventional circumstances, and an object thereof is to obtain a drive shaft device that does not impair the durability of the bearing.

[0005]

Therefore, the present invention has a drive shaft rotatably supported by a housing via a bearing, and a pulley attached to a projecting end of the drive shaft from the housing. In the drive shaft device for rotationally driving the drive shaft, the drive shaft is arranged between the bearing and the pulley, and the drive shaft is provided with a flexible portion having low rigidity. Further, as the flexible portion, a groove having an arcuate bottom surface is formed on the outer periphery of the drive shaft.

[0006]

The belt wound around the pulley rotates the pulley with a predetermined tension. When the tension of the belt acts on the drive shaft and a bending moment acts on the drive shaft, the flexible portion having a low rigidity bends, so that the maximum bending moment acting on the bearing portion of the drive shaft is relaxed. As a result, the contact surface pressure of the bearing is reduced, and the durability of the bearing is not impaired.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a sectional view of an essential part of a drive shaft device showing an embodiment of the present invention, and is a drawing showing an example of application to a cooling water circulating water pump of an internal combustion engine. In the figure, 1 is a housing,
The housing 1 is attached to the engine body 2 and forms a pump chamber 3 with the engine body 2. Reference numeral 4 denotes a drive shaft, which is mounted on a housing 1 through a bearing 6 housed in a support hole 5 formed in the housing 1.
It is rotatably supported with respect to. The bearing 6
Is a bearing of a double row rolling element composed of rollers 8 and balls 9 held by a retainer 7, and the balls 9 roll in rolling grooves 11 respectively provided on the outer circumference of the drive shaft 4 and the inner circumference of the outer ring 10. The seal member 12 is provided between the drive shaft 4 and the drive shaft 4 at both ends.
It has been sealed by.

Reference numeral 13 is a pulley attached to the projecting end 4a of the drive shaft 4 from the housing 1.
The inner peripheral boss portion 14 is attached to the pulley seat 15 which is press-fitted and fixed to the drive shaft 4 by the bolt 16, and is rotationally driven by the belt 18 wound around the outer peripheral groove portion 17.

The drive shaft 4 is provided with a low-rigidity flexible portion 19 located between the bearing 6 and the pulley 13. In this embodiment, the flexible portion 19 is a groove 20 having a circular arc bottom surface, and the bottom surface of the groove 20 can be finished into a smooth surface in order to avoid a decrease in strength due to a notch effect. . Further, it is desirable that the depth of the groove 20 is equal to or greater than the hardening depth when the drive shaft 4 is hardened.

A pump impeller 21 formed by pressing a plate member is attached to the end 4b of the drive shaft 4 on the pump chamber 3 side. Further, a mechanical seal 22 is provided between the housing 1 and the drive shaft 4. This mechanical seal 22 has a structure in which the seal member 26 is pressed against the carbon 23 attached to the drive shaft 4 by the spring force of the spring member 25 attached to the metal plate 24 attached to the housing 1.
It controls the liquid-tight sealing between the pump chamber 3 and the inside of the support hole 5. In addition, 27 is a steam vent hole penetrating the housing 1 and opening in the support hole 5, and 28 is a similar water vent hole, which discharges the cooling water and the steam leaked into the support hole 5, and the cooling water and the steam. It is prevented from invading the bearing 6 and adversely affecting the bearing 6.

In this structure, the pulley 18 is rotated by the belt 18 wound around the pulley 13,
The drive shaft 4 is rotationally driven. As a result, the pump impeller 21 attached to the end 4b of the drive shaft 4 rotates,
The cooling water guided from the suction passage 29 is discharged to the discharge passage 30,
Circulate at a predetermined location of the internal combustion engine.

Here, since the belt 18 is acted on by a predetermined tension F to rotate the pulley 13, a bending moment acts on the drive shaft 4, but a flexible portion 19 having a low rigidity.
By bending, the bending moment at the bearing 6 portion of the drive shaft 4, which mechanically serves as a fixed portion of the cantilever, is relaxed. As a result, the contact surface pressure of the bearing 6, more specifically, the contact surface pressure of the roller 8 or the ball 9 against each rolling surface, is reduced, so that the durability of the bearing 6 is not impaired and the durability is improved. Can be achieved. Since the groove 20 is provided as the flexible portion 19 on the outer periphery of the drive shaft 4, the rigidity of the flexible portion 19 can be arbitrarily selected by selecting the depth of the groove 20.

Although the embodiment has been described with reference to the drawings, the specific structure is not limited to this embodiment.
Modifications can be made without departing from the spirit of the invention. For example, although an example in which the flexible portion 19 is provided with a groove 20 having an arc bottom surface has been described, the bottom surface of the groove is not necessarily arcuate. When a drive shaft that has been subjected to a surface hardening treatment is adopted, the hardening-prevented treatment is applied to an appropriate portion of the drive shaft and then the hardening treatment is applied to the flexible shaft having a low rigidity. May be set.
Furthermore, it is optional to employ a combination of groove formation and hardening prevention treatment, such as performing hardening prevention treatment on the groove formed as the flexible portion. Furthermore, without being limited to water pumps,
The drive shaft device of the present invention can be applied to various rotary devices.

[0015]

As described above in detail, according to the present invention, the drive shaft rotatably supported by the housing via the bearing and the pulley attached to the projecting end of the drive shaft from the housing. In the drive shaft device that has the pulley and drives the drive shaft to rotate, the tension of the belt is reduced by providing a flexible portion having a low rigidity, which is located between the bearing and the pulley and has a low rigidity. When a bending moment acts on the drive shaft and acts on the drive shaft, the maximum bending moment acting on the bearing portion is relaxed by bending the flexible portion, which reduces the contact surface pressure of the bearing.
The durability of the bearing is not impaired and the durability can be improved. Further, as the flexible portion, by forming a groove having an arcuate bottom surface on the outer circumference of the drive shaft, it is possible to select the depth of the groove and arbitrarily select the rigidity of the flexible portion.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a drive shaft device showing an embodiment of the present invention.

[Explanation of symbols]

 1 Housing 4 Drive shaft 4a Projecting end 6 Bearing 13 Pulley 19 Flexible part 20 Groove

Claims (2)

[Claims] 1. A drive shaft having a drive shaft rotatably supported by a housing via a bearing and a pulley attached to a projecting end of the drive shaft from the housing, wherein the drive shaft is rotationally driven by the pulley. In the device, the drive shaft device is provided between the bearing and the pulley, and a flexible portion having low rigidity is provided on the drive shaft. 2. The drive shaft device according to claim 1, wherein the flexible portion is a groove having an arcuate bottom surface provided on the outer periphery of the drive shaft.