JPS6116217Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention supports a gear box for a steering device of a vehicle, particularly a rack rod, a pinion shaft that meshes with the rack rod, and a guide piston that presses the pinion shaft against the rack rod with a spring force. Regarding gear boxes.

Conventionally, the above-mentioned gear boxes are known to be made entirely of aluminum alloy, or partially made of aluminum alloy, with the other parts made of steel pipes, and both parts are press-fitted together. In the former case, since the gear box has an elongated shape in the left-right direction of the vehicle, there is a high defect rate due to poor hot water circulation during casting, and the material cost is relatively high, resulting in high costs. Although the latter is more advantageous than the former in terms of material costs, it is not easy to manufacture and has poor mass productivity because the machining accuracy of the press-fit joint must be strictly controlled to ensure the specified strength of the press-fit joint. .

The present invention was proposed in view of the above, and includes a first housing that supports the gear box and a rack rod.
The second housing supports the pinion shaft that engages with the rack rod, and the third housing supports the guide piston that presses the rack rod toward the pinion shaft with spring force.The housings are separated into three parts by steel pipes. In particular, the first housing is formed from a butted pipe having a thick-walled cylindrical portion at one end,
It is an object of the present invention to provide the gear box which does not have the drawbacks of the conventional gear box by welding the second and third housings and the holder connected to the vehicle body to the thick-walled cylindrical part.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Reference numeral 1 denotes a gear box fixed to the vehicle body, and a rack rod 2 extending in the left-right direction of the vehicle passes through the inside of the gear box 1, and the rack rod 2 is slidable. A supporting bearing bush 3 is fitted into the left end of the gear box 1. Tie rods 5, 5' connected to left and right steering wheels (not shown) are connected to both left and right ends of the rack rod 2 via ball joints 4, 4', respectively.

A pinion shaft 6 extending substantially perpendicularly to the rack rod 2 is rotatably supported on the gear box 1 via a ball bearing 7 and a bearing bush 8, and a pinion 6a of the pinion shaft 6 and a rack 2a of the rack rod 2 are engaged. The pinion shaft 6 is rotated by a steering handle (not shown).

Further, a guide piston 9 that slidably supports the side surface of the rack rod 2 on the side opposite to the pinion shaft 6 is fitted into the gear box 1, and a cap 1 to prevent it from slipping out is fitted into the gear box 1.
0 is screwed. A rack rod 2 is connected between the guide piston 9 and the cap 10 via the piston 9.
A spring 11 is provided to compress the pinion shaft 6 toward the pinion shaft 6, thereby eliminating backlash at the meshing portion of the rack 2a and pinion 6a.

The gear box 1 includes a first housing 1a that supports a rack rod 2 via a bearing bush 3;
A second housing 1 that supports a pinion shaft 6 via a ball bearing 7 and a bearing bush 8
b, and a third housing 1c which supports the guide piston 9 and into which the cap 10 is screwed, and these housings 1a, 1b, and 1c are each formed from a steel pipe. In particular, the first housing 1a is formed from a butted pipe having a thick-walled cylindrical portion 12 at its right end.

An engagement hole 13 is provided at one end of the thick-walled cylindrical portion 12 of the first housing 1a with which approximately half the circumferential surface of the second housing 1b engages. , 1b are provided with windows 14 that communicate with each other to allow engagement of the rack 2a and the pinion 6a, and welding 15 is performed along the outer periphery of the engagement hole 13 to connect the thick-walled cylindrical portion 12 to the second housing. 1b is combined. Further, on the other side of the first housing 1a, there is a window 16 that allows the guide piston 9 to enter into the housing 1a, and on the end surface of the third housing 1c, the outer peripheral surface of the thick-walled cylindrical portion 12 is engaged. Engagement recesses 17 are provided, respectively.
The third housing 1c is coupled to the thick-walled cylindrical portion 12 by welding 18 along the outer peripheral edge of the engagement recess 17.

The right end opening of the thick-walled cylindrical portion 12 is expanded in diameter to an enlarged portion 12a that receives a part of the right ball joint 4' at the leftward limit of movement of the rack rod 2, and a raised portion is formed on the outer peripheral surface of this enlarged portion 12a. A pair of annular protrusions 19, 19'
This creates a mounting groove 21 for a dust boot 20' that protects the right exposed portion of the rack rod 2.

Furthermore, a pair of annular protrusions 22 and 22' are formed on the outer circumferential surface of the left end of the first housing 1a, and these provide a mounting groove 21 for the dust boot 20 that protects the left exposed portion of the rack rod 2. is created.

Furthermore, the first housing 1a has the above-mentioned mounting groove 2.
The locking hole 23 with which the locking protrusion 3a of the bearing bushing 3 engages is located slightly to the right from the locking hole 23, and the insertion position of the bushing 3 is located further to the right from the locking hole 23. Positioning protrusion 24 that regulates
are respectively provided, and the protrusions 24 are formed by bulges on the inner surface of the first housing 1a. Therefore, no thick wall portion is required at the left end portion of the first housing 1a.

A thick cylindrical portion 1 is provided on the outer peripheral surface of the first housing 1a.
2 and the vicinity of the bearing bush 3, holders 25 and 25' are welded 26 and 26', respectively,
The gear box 1 is fixed to the vehicle body by connecting these holders 25, 25' to the vehicle body via clamps (not shown).

In the figure, 27 is a sealing member, 28 is a cover, and 2
9 is a plug.

When the operator rotates the pinion shaft 6 clockwise or counterclockwise using a steering handle (not shown), the rack 2a is driven from the pinion 6a, and the rack rod 2 moves to the left or right, resulting in a steering wheel (not shown). The direction wheels can be turned to the right or left.

During such steering, the first housing 1a
Large loads are applied from various directions, especially to the thick-walled cylindrical portion 12 around the pinion shaft 6, but the thick-walled cylindrical portion 12 itself has high strength, and the second and third housings 1b and 1c welded to it and holder 25'
etc., so it can sufficiently withstand the above load.

As described above, according to the present invention, the gear box is divided into three parts: the first housing that supports the rack rod, the second housing that supports the pinion shaft, and the third housing that supports the guide piston. Since the housings are individually formed from steel pipes and joined together by welding, the gear box can be manufactured easily and with high yield from inexpensive steel pipes.The above welding can be easily automated, so mass production is high and costs are reduced. can contribute to

Moreover, the first housing is formed from a butted pipe having a thick-walled cylindrical portion at one end, and the second and third housings and the holder are welded to the thick-walled cylindrical portion, thereby further reinforcing the thick-walled cylindrical portion. is,
Therefore, while ensuring sufficient strength, wasteful meat can be eliminated and weight reduction can also be achieved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional plan view of a steering device showing an embodiment of the present invention, and FIG. 2 is a lateral sectional view taken along the - line in FIG. 1. 1... Gear box, 1a... First housing, 1b
...Second housing, 1c...Third housing,
2... Rack rod, 2a... Rack, 6... Pinion shaft, 6a... Pinion, 9... Guide piston,
12...Thick-walled cylinder part, 15...Welding, 18...Welding, 25'...Holder, 26'...Welding.

Claims (1)

[Scope of utility model registration request] a first housing 1a that slidably supports the rack rod 2; a second housing 1b that rotatably supports the pinion shaft 6 that meshes with the rack rod 2;
A third housing 1c that slidably supports a guide piston 9 that presses the rack rod 2 toward the pinion shaft 6 with a spring force is formed individually from a steel pipe, and in particular, the first housing 1a has a thickness at one end. The second and third housings 1b and 1 are formed from a butted pipe having a thick-walled cylindrical portion 12.
c and the holder 25' connected to the vehicle body.
5, 18, 26', a gear box for a steering device of a vehicle.