JPS5929146Y2 - Pulley fixing device for hydraulic pump for power steering system - Google Patents

Description

[Detailed description of the invention] This invention relates to a device for fixing a pulley to a hydraulic pump for a power steering device used to rotationally connect a hydraulic pump and an engine in a power steering device for a vehicle using a belt. It is.

Since the internal space of a vehicle's engine room is extremely limited, it is important not only to have the size of the hydraulic pump itself, but also to ensure that the pulley attached to the drive shaft is installed with as short an axial length as possible. preferable.

In a conventional pulley fixing device for a hydraulic pump for a power steering device, as shown in FIG.
The half-moon key 5 is engaged with the arc-shaped groove provided therein and the axial keyway 7 provided in the shaft hole 6, and the seat plate 4 is abutted against the end of the pulley 2. , and the threaded shaft portion 1 of the drive shaft
The pulley 2 is fixed by tightening the nut 3 at c.

In such a conventional pulley fixing device for a hydraulic pump for a power steering device, in addition to the shaft hole 6 of the pulley 2 and the axial length of the boss portion, the seat plate 4 and the nut 3 are attached to the drive shaft 1. The drive shaft 1 becomes longer by the amount of support, which is not preferable.

Also, Utility Model Application Publication No. 52-82101 and Utility Model Application No. 51-1
As shown in Japanese Patent No. 48578, a hollow space or a tapered screw hole is provided at the end of the drive shaft, a split groove is provided in the tapered screw hole, and the end of the drive shaft is fitted into the shaft hole of the pulley. Furthermore, it has been proposed that the end of the drive shaft and the shaft hole of the pulley are tightly fitted by fitting or screwing a conical wedge or a tapered screw into the hollow portion or the tapered screw hole. However, this not only takes time and effort to process split grooves and tapered screw holes, but there is also a limit to how strongly a wedge or taper screw can be screwed into a hollow space or taper screw hole, resulting in a large load torque on the drive shaft. has limited power.

Therefore, the purpose of this invention is to provide a fixing device for a pulley to a hydraulic pump for a power steering system, which allows easy and reliable attachment of a pulley to a drive shaft, has a large transmission torque, and can significantly shorten the installation length of the drive shaft. Our goal is to provide the following.

For this reason, the configuration of the present invention is to provide a small-diameter shaft portion for fitting the pulley at the tip of the drive shaft, and to form a thin-walled cylindrical portion by cutting a hole opening toward the tip side at the axis of the small-diameter shaft portion. and press-fitting a ball into the thin-walled cylindrical portion to expand the thin-walled cylindrical portion;
The thin cylindrical portion is frictionally engaged with the shaft hole of the pulley.

The present invention will be explained based on examples.

As shown in FIG. 2, a small diameter shaft portion 1b is formed at the tip of the drive shaft 1 from the stepped portion 1a, and this small diameter shaft portion 1b is connected to the pulley 2.
A thin-walled cylindrical portion 20 is formed by fitting into the shaft hole 6 of the drive shaft 1 and cutting a tapered hole 12 that shares a central axis with the drive shaft 1 and has a large diameter on the tip side.

Then, by firmly driving the ball 13 into the tapered hole 12, the thin cylindrical portion 20 is expanded radially outward to create a deformed portion 15, which is strongly frictionally engaged with the shaft hole 6 of the pulley 2. This is how it was done.

If necessary, the opening end of the tapered hole 12 is deformed into a radial force using a punch h, etc., and the Yotte hole 13 is inserted into the deformed portion 14.
It is preferable to avoid omissions.

Since the present invention is constructed as described above, it is sufficient that the drive shaft 1 is provided with a small diameter shaft portion 1b having the same dimensions as the length of the boss portion of the pulley 2 at the tip end, which is different from the conventional example shown in FIG. Since the screw shaft portion 1c that engages the seat plate 4 and the nut 3 is not required as shown in FIG. It also helps reduce costs because it doesn't.

Note that in the above embodiment, the ball 1 is used instead of the tapered hole 12.
A right circular hole with a diameter slightly smaller than 3 may also be used.

As explained above, the present invention is a device for fixing a pulley to a hydraulic pump for a power steering device, by forming a thin cylindrical part by drilling a hole in the pulley mounting shaft of a drive shaft, and attaching the pulley to the drive shaft. After fitting the pulley onto the shaft, the thin cylindrical portion is expanded by press-fitting the ball into the hole, so the drive shaft is tightly fitted into the shaft hole of the pulley, so a large torque can be generated. can be transmitted.

Driving the ball in with a hammer is much easier to assemble than in the case of a tapered screw, and unlike a tapered screw, which uses frictional force to prevent the ball from coming out, the ball can be driven in by driving it in force. The hole into which the ball is fitted is deformed to be wider than the diameter of the inlet side through which the ball passed, and the ball is elastically bitten into it, so this also provides a highly reliable retaining effect. .

Furthermore, since the configuration is extremely simple and assembly is easy, costs can be significantly reduced compared to conventional examples.

In addition, since the end of the drive shaft only needs to be as long as the pulley fitting part, the length of the drive shaft can be significantly shortened compared to conventional models, and it can be used in internal spaces such as engine compartments. When the hydraulic pump is installed in a limited area of the engine, an excellent effect can be obtained in that the arrangement becomes easy.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing a conventional pulley fixing device for a hydraulic pump for a power steering device, and FIG. 2 is a side sectional view showing a pulley fixing device for a hydraulic pump for a power steering device according to the present invention. be. 1... Drive shaft, 1b... Small diameter shaft portion, 2
...Pulley, 6...Shaft hole, 12...
...Hole, 13...Ball 14.15...
Deformed part, 20... Thin cylindrical part.

Claims (1)

[Scope of utility model registration request] A small-diameter shaft portion for fitting a pulley is provided at the tip of the drive shaft, a hole that opens at the tip end of the small-diameter shaft portion is cut to form a thin-walled cylindrical portion, and a ball is inserted into the thin-walled cylindrical portion. A device for fixing a pulley to a hydraulic pump for a power steering device, characterized in that the thin-walled cylindrical portion is press-fitted to expand the thin-walled cylindrical portion, and the thin-walled cylindrical portion is frictionally engaged with the shaft hole □ of the pulley.