JPH042467B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a rack and pinion type steering gear device.

(Prior art) As a type of steering gear device, a rack-pinion type steering gear device has the advantage of being highly rigid, compact, and does not require special manufacturing techniques, and has a rack engaged with a pinion rotated by a handle. is widely adopted.

(Problem to be Solved by the Invention) However, one drawback of this rack and pinion type steering gear device is that the minimum diameter (minimum number of teeth) of the pinion cannot be made very small due to restrictions on ensuring strength, and as a result, deceleration occurs. The problem is that the ratio cannot be made very large.

Therefore, even if the vehicle is relatively small, for example, in the case of a front-wheel drive vehicle with a large front wheel steering load, it is desirable to install a power assist device to reduce the steering force.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a steering gear device which is a rack and pinion type but allows the reduction ratio to be freely selected, and in particular allows a steering force reduction ratio, and is also equipped with a backlash adjustment function. be.

(Means for Solving the Problems) In order to solve the above problems and achieve the objectives, the present invention connects a first pinion shaft 11 that rotates in conjunction with a handle and left and right tie rods in a gearbox 1. A second pinion shaft 21 is provided, which incorporates a supporting rack shaft 8 and includes a pinion 23 that meshes with the rack 9 of the rack shaft 8 and a pinion 22 that meshes with the pinion 12 of the first pinion shaft 11.
A bearing cage 31 for bearing and holding the second pinion shaft 21 is provided, and preload mechanisms 41 and 46 are provided between the bearing cage 31 and the gearbox 1, and the bearing cage 31 is loaded via the preload mechanisms 41 and 46. The present invention is characterized by a steering gear device built into the gear box 1.

(Function) Since it becomes possible to obtain a sufficient reduction ratio between the first pinion shaft 11 and the second pinion shaft 2, the steering force can be reduced even without adding a power assist device. Since the preload mechanisms 41 and 46 are provided between the gear box 1 and the bearing cage 31 that supports the second pinion shaft 21, backlash adjustment of all gears can be easily performed.

(Example) Examples will be described in detail below based on the accompanying drawings.

Figure 1 is an external perspective view of the steering gear box, Figure 2 is a perspective view of the principle of the gear, and Figure 3 is a perspective view of the steering gear box.
The figure is a longitudinal side view of the inside of the gearbox.

As is known, a rack shaft 8 that connects and supports left and right front wheel tie rods and a first pinion shaft 11 that is rotated by a handle are installed in the steering gear box 1 so as to be orthogonal to each other.

The gearbox 1 is closed at the front with a cover 7,
A rack shaft 8 is slidably supported in the left and right direction by cylindrical bosses 2, 2 projecting left and right at the front, and a first pinion shaft 11 is assembled from the rear into a cylindrical boss 3 projecting rearward. A pinion 12 is formed in the middle part of the first pinion shaft 11, a ball bearing 15 is interposed between the shaft part behind the pinion 12 and the boss 3, and a ball bearing 15 is installed between the shaft part ahead of the pinion 12 and inside the gear box 1. A needle bearing 16 is installed between the bearing bosses 4.
Interpose. 17 in Figure 3 is a seal, 18, 19
is a stoppering.

In this way, the rack shaft 8 and the first pinion shaft 11 are installed in the gearbox 1 at the front and rear.

A second pinion shaft 21 serving as an intermediate shaft is disposed in the space of the gear box 1 above the rack 9 of the rack shaft 8 and the pinion 12 of the first pinion shaft 11. The second pinion shaft 21 includes pinions 22 and 23 at the front and rear of the intermediate portion, and a pinion 2 at the rear.
2 has sufficiently more teeth than the pinion 12 of the first pinion shaft 11, and the front pinion 23 has fewer teeth than the rear pinion 22. The pinion 12 of the shaft 11 is engaged, and the front pinion 23 is engaged with the rack 9.

Further, the second pinion shaft 21 is connected to the bearing cage 3.
Hold the bearing at 1. The bearing cage 31 has a box 32 at the front, a cylindrical boss 33 at the rear, and left and right side walls 35, 35 forming a window 34 penetrating in the vertical direction at the middle, as shown in FIGS. 4 and 5. The bearing boss 38 of the cap 37 is fitted into the front box 32, and the cap 37 is connected to the box 32 with bolts 39.

The needle bearing 25 is interposed in the bearing boss 38 of the cap 37 fitted in the front box 32 of the bearing cage 31, and supports the shaft portion of the second pinion shaft 21 in front of the front pinion 23. A needle bearing 26 is interposed in the rear cylindrical boss 33, and supports the shaft portion rearward of the rear pinion 22.

Thus, a backlash adjustment device is constructed between the gearbox 1 and the bearing cage 31 bearing and holding the second pinion shaft 21.

First, spherical holes 36 , 36 are formed on the upper surface of the intermediate portions of the left and right side walls 35 , 35 of the bearing cage 31 , and set screws 41 , 41 having spherical tips facing the spherical holes 36 , 36 are inserted into the gearbox 1 . Screw into the upper mold. These push screws 41, 41 are connected to the spherical hole 36,
36 and presses the bearing cage 31 downward to position the two sets of gear meshing parts of the pinions 12, 22, the pinion 23, and the rack 9 so that they do not come off and do not become stiff. and push screw 4
1 and 41 with nuts 42 and 42 to fix them.

Further, bottomed cylindrical screws 45, 45 are screwed into the front and rear of the upper mold of the gear box 1 where the front and rear boxes 32 and cylindrical boss 33 of the bearing cage 31 are located, and the preload springs 46, 45 are inserted into the cylindrical screws 45, 45. 46, and the lower portions of the springs 46, 46 are brought into pressure contact with the upper surface of the box 32 and the cylindrical boss 33 of the bearing cage 31, and the bearing cage 31 is always pressed downward by the springs 46, 46. Nuts 47, 47 are then fastened and fixed to the cylindrical screws 45, 45.

As described above, the pinions 22 and 2 that mesh with the rack 9 and pinion 12 are installed in the gear box 1 in which the rack shaft 8 and the first pinion shaft 11 are assembled in advance.
A bearing cage 31 bearing and holding a second pinion shaft 21 having a second pinion shaft 21 is assembled via push screws 41, 41 and preload springs 46, 46, which constitute a preload mechanism for backlash adjustment.

In this way, since the second pinion shaft 21 is interposed between the first pinion shaft 11 and the rack shaft 8 and includes the pinions 22 and 23 that mesh with the respective pinions 12 and racks 9, the pinion 12 of the first pinion shaft 11 and the pinion 22 of the second pinion shaft 21
By selecting the number of teeth, the reduction ratio can be freely increased without any restrictions on strength. This allows the steering force to be significantly reduced compared to conventional methods.
Even when power assistance was required in the past, it can be handled with a simple non-powered mechanism.

Incidentally, since the reduction ratio can be changed by simply replacing both the first and second pinion shafts 11 and 21, the large gear box 1 and the bearing cage 31 are commonly used.

Furthermore, in order to adjust the position of the bearing cage 31 that holds the second pinion shaft 21 with the two push screws 41, 41, the backlash adjustment of the two sets of gear meshing parts of the pinions 12, 22, the pinion 23, and the rack 9 is simultaneously adjusted. , the clearance of the two bearings 25 and 26 of the second pinion shaft 21, the clearance of the two bearings 15 and 16 of the first pinion shaft 11, and the clearance of the bearing part of the rack shaft 8. , 41.

In addition, the bearing cage 31 is connected to two preload springs 4.
6 and 46 constantly press downward, even if the gear meshing part and the bearing part wear out, the occurrence of clearance can be prevented by automatic adjustment, and there is no need to worry about rattling.

Through such backlash adjustment and clearance adjustment, the machining accuracy of the main body of the gearbox 1 can be rougher than the conventional one in which the first pinion shaft and the easy shaft are directly engaged with gears.

(Effects of the Invention) As described above, according to the present invention, in the rack and pinion steering gear device, the first pinion shaft and the rack shaft, which rotate in conjunction with the steering wheel, are engaged with each other between the first pinion shaft and the rack shaft. Since a second pinion shaft having two pinions is provided, a particularly large reduction ratio can be obtained by freely selecting the reduction ratio, so that it is possible to reduce the steering force without requiring a power assist device. Furthermore, since a bearing cage for bearing and holding the second pinion shaft is provided, and a preload mechanism is provided between the bearing cage and the gear box, there is no need for individual backlash adjustment, and the backlash adjustment of all gears can be easily performed.

[Brief explanation of drawings]

Fig. 1 is an external perspective view of the steering gear box, Fig. 2 is a perspective view of the principle of the gear, Fig. 3 is a sectional view taken along the line shown in Fig. 1, and Fig. 4 is Fig. 3 -
The line sectional view and FIG. 5 are plan views of the bearing cage portion. In addition, in the drawing, 1 is the gearbox, 8 is the rack shaft,
9 is a rack, 11 is a first pinion shaft, 12 is a pinion, 21 is a second pinion shaft, 22, 23 are pinions, 31 is a bearing cage, 41 is a push screw, 46
is a preload spring.

Claims (1)

[Scope of Claims] 1. A first pinion shaft that rotates in conjunction with the handle and a rack shaft that connects and supports the left and right tie rods are incorporated into a gearbox, and a pinion that meshes with the rack of the rack shaft and the first A second pinion shaft including a pinion that meshes with a pinion of the pinion shaft is provided, a bearing cage is provided for bearing and holding the second pinion shaft, and a preload mechanism is provided between the bearing cage and the gear box, and the preload mechanism is provided. A steering gear device characterized in that the bearing cage is assembled into the gearbox via the gearbox.