JPS6311014Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a bevel gear device in a vehicle steering system. More specifically, the present invention relates to a friction adjustment device for a bevel gear connected to a rack and pinion steering device, mainly in a cabover type vehicle.

In cab-over type vehicles, due to the relative position between the steering wheel and the front wheels, the transmission path must be bent midway in order to transmit the steering force from the steering wheel to the front wheels, and for this purpose a bevel gear device including a pair of bevel gears is used. is used. One bevel gear is integral with the input shaft rotated by the steering wheel, and the other bevel gear is integral with the output shaft connected to the rack and pinion steering system.

In such a bevel gear device, a frictional force may be applied to the bevel gear. This is to prevent wobbling due to slight bumps in the bevel gear mesh due to vehicle vibrations or bumps, and to limit shocks from being transmitted directly to the steering wheel to ensure stable steering. . The friction force is obtained, for example, by pressing a friction member (friction block) against the end face of the bevel gear on the input shaft side.

In conventional friction force adding devices, the friction block is pressed directly against the end face of the bevel gear, so it is difficult to set the magnitude of the pressure, that is, the magnitude of the friction force relative to the rotation, and it is difficult to set the magnitude of the pressure. It took a lot of time to set up. Additionally, if the end face of the small diameter side of the bevel gear is bent due to minute deformation due to part processing or heat treatment, the friction block may not contact the bevel gear properly, or
The friction block sometimes fell off.

The present invention solves the drawbacks of the conventional example described above. In other words, the backlash of the bevel gear is appropriately adjusted and maintained, and the rotation of the bevel gear on either the input shaft or the output shaft can be adjusted to a desired magnitude. To provide a frictional force of 100% and thereby prevent the steering wheel from wobbling due to minute crushing of the bevel gear meshing part due to vibrations of the vehicle, etc.
This is intended to prevent shocks from the output shaft side from being directly transmitted to the steering wheel.

In order to achieve the above object, in the present invention, either the input shaft or the output shaft is attached to the gear case so that it can be fixed in a predetermined position in the axial direction via a bearing, and the other is attached to the bevel gear and one shaft. It can be moved in the axial direction to maintain proper backlash with the bevel gear, and can be fixed in that position via a bearing after movement, and furthermore,
An adjustment member is disposed on the small-diameter end face of the bevel gear of the other shaft so as to be able to approach or separate from it, and a friction block is attached to the tip of the adjustment member via an elastic member such as a spring. Therefore, the friction block is pressed against the end face of the bevel gear, and can apply an appropriate frictional force to the rotation of the other shaft.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram of a steering system of a cab-over type vehicle, in which a steering shaft B supporting a steering wheel A is connected to an input shaft 1 of a bevel gear device D via a coupling C. The output shaft 5 of the bevel gear arrangement D is connected to a rack and pinion steering arrangement G via two couplings E, F.

FIG. 2 shows the structure of the bevel gear device D in detail. In the figure, an input shaft 1 has a bevel gear 4 at its tip, a needle bearing 2 held in a gear case 7, and a ball bearing fitted into a rear cover 8 screwed to the gear case 7 and prevented from coming out by a retaining ring 9. It is rotatably supported by 3. Therefore, by rotating the rear cover 8, the input shaft 1 can be moved in the axial direction, and the position of the bevel gear 4 can be adjusted.

A lid 24 is attached to the gear case 7 with bolts 23, and an adjustment bolt 13 is screwed into a portion of the lid 24 that faces the small-diameter end surface 10 of the bevel gear 4. As shown in detail in FIG. 3a, a friction block 11 is loosely fitted into the small diameter portion of the bolt 13, and the block 11 is prevented from falling off from the tip 14 by a wire ring 22. Block 11
is movable by a distance δ relative to the tip 14. To prevent it from falling off, as shown in Figure 3b, the tip 1
You can also do this by caulking step 4.

Further, the block 11 is biased in a direction protruding from the tip 14 by a spring member 12 interposed between the block 11 and the end surface of the bevel gear 4.
are being oppressed. End face 10 by block 11
The elastic force can be adjusted by rotating the bolt 13, and thereby the frictional force against the rotation of the input shaft 1 can be selected to a desired magnitude.

The relationship between the distance δ and the rotational torque of the input shaft 1 is the fourth
As shown in the figure. As is clear from the figure, δ
The rate of change in rotational torque with respect to change in is relatively small. Therefore, by rotating the adjustment bolt 13 and adjusting the distance δ, the magnitude of rotational torque can be accurately adjusted to a predetermined value. can.

Furthermore, the friction block 11 is capable of swinging, that is, tilting, and even if the small-diameter end face 10 of the gear falls down due to minute deformation due to parts processing or heat treatment, it can swing to follow that plane, and the spring member 12 Can move back and forth. As a result, since the position of the conventional friction block does not change, the axial movement of the small-diameter end face of the gear due to the manufacturing error or engagement creates a gap between the end face and the friction block. While there are situations in which the frictional force becomes zero or becomes extremely large, in the present invention, this condition can sufficiently absorb fluctuations in torque due to rotation.

On the other hand, the output shaft 5 has the bevel gear 4 at its tip.
It has a bevel gear 6 that meshes with the gear case 7, and is rotatably supported by a needle bearing 15 and a ball bearing 16 fitted to the gear case 7, and is rotatably supported by the machined surface part 1 of the gear case 7.
A needle roller bearing 19 is interposed between the bevel gear 8 and the large-diameter end surface 17 of the bevel gear 6, and is tightened by a nut 20 that is screwed onto the output shaft 5 while preventing axial movement.

The reason why the output shaft 5 is held between both sides by the needle roller bearing 19 and the nut 20 is that the non-gear side of the output shaft 5 is connected to the rack and pinion type steering via a coupling, so there is no possibility of stiffness or installation errors on the vehicle side. etc., the output shaft 5
This is to prevent the gear from being pushed out toward the gear side. When this pushing movement occurs, the bevel gears 4 and 6 of the input shaft 1 and the output shaft 5 become in a meshed state with no backlash, thus preventing smooth rotation and impairing steering performance. By properly tightening the nut 20, the ball bearing 1
It is possible to prevent looseness due to the assembly gap 6, and the two-faced portion 21 of the nut is caulked to prevent loosening.

As described above, according to the present invention, the battery is properly held and, for example,
Since the friction block 11 is pressed against the bevel gear 4 of one shaft 1 to apply a frictional force to the rotation of the shaft 1, the steering is prevented by slight backlash of the bevel gear meshing part against vehicle vibrations or jerkbacks. Wobble of the wheel is prevented (absorbed and alleviated by frictional force), and direct transmission of impact to the steering wheel A is restricted. Also, the friction block 11 is connected to the spring member 12.
Since the force is applied to the bevel gear 4, the magnitude of the frictional force applied to the bevel gear 4 can be precisely controlled, wear of the friction surface is corrected, and the frictional force can be applied optimally.

Further, in the above embodiment, the output shaft 5 is positioned in the axial direction by the needle bearing 19, the ball bearing 16, and the nut 20 screwed onto the shaft 5, and the input shaft 1 is held on the ball shaft 3 and is connected to the gear case. Since the axial position is adjusted and fixed at that position by the rear cover 8 screwed onto the bevel gears 7, the backlash between the bevel gears 4 and 6 is set correctly to a predetermined size, and once set, This state will never collapse.

Further, since the friction block 11 is made tiltable, even if the bevel gear 4 falls down due to minute deformation, the friction block will tilt to follow the small diameter side end face and apply a predetermined frictional force. Furthermore, since the friction block 11 is attached via the wiring 22, there is no fear that the friction block 11 will fall off.

In the above embodiment, the input shaft 1 is biased and pressed by the friction block 11, but it may be the output shaft 5. This is because it is sufficient to apply frictional resistance somewhere along the path from the steering wheel 4 to the steering device.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of a steering system, Fig. 2 is a sectional view showing an embodiment of the present invention, Fig. 3a is an enlarged view of Fig. 2, and Fig. 3b is a sectional view showing a modification thereof. , 4th
The figure is a graph showing the relationship between the amount of movement of the preload block and the rotational torque of the input shaft 1. Explanation of symbols of main parts, 1... Input shaft, 4, 6
... Bevel gear, 5 ... Output shaft, 11 ... Friction block, 7 ... Gear case, 8 ... Rear cover,
12... Spring member, 13... Adjustment bolt, 20...
...Natsuto.

Claims (1)

[Claims for Utility Model Registration] 1. An input shaft having a bevel gear at one end and connected to a steering wheel at the other end, and a bevel gear intersecting with the input shaft and meshing with the bevel gear at one end, and at the other end. It consists of an output shaft connected to a wheel steering device, a gear case accommodating the input shaft and the output shaft, and a plurality of bearings rotatably supporting the input shaft and the output shaft in the gear case. In a bevel gear device in a vehicle steering system in which rotational force is transmitted to a vehicle steering device, either the input shaft or the output shaft is
A first bearing that is interposed between the large-diameter end face of the bevel gear of the shaft and the gear case and can receive a thrust load, and a first bearing that is fitted between the gear case and the gear case at a position axially distant from the first bearing. a second bearing mounted on the shaft and capable of receiving at least a thrust load; a thread is formed in a portion of the shaft located on one side of the second bearing; a nut is screwed onto the thread; The one shaft is fixed at a predetermined position in the axial direction with respect to the gear case by contacting the second bearing, and the other shaft is fixed between a position of the shaft remote from the bevel gear and the gear case. A screw is formed in the open part of the gear case that accommodates the other end of the shaft, and a rear cover is screwed onto the screw. The third bearing is fitted, and rotation of the rear cover causes the third bearing to be fitted.
The other shaft is moved in the axial direction via a bearing, whereby the backlash of both the bevel gears is properly adjusted, and the gear case has a shaft that approaches or separates from the small-diameter end face of the bevel gear of the input shaft or the output shaft. an adjusting member whose movement amount in the direction of the bevel gear can be adjusted; a friction block is attached to the tip of the adjusting member via an elastic member; the friction block is elastically pressed against the small-diameter end surface of the bevel gear;
A friction adjustment device for a bevel gear device in a vehicle steering system, characterized in that it provides frictional resistance to the rotation of the bevel gear. 2. The friction adjustment device for a bevel gear device in a vehicle steering system according to claim 1, wherein the adjustment member is an adjustment bolt screwed into the gear case, and the elastic member is a spring. 3. The friction block is loosely fitted into the small diameter portion of the adjustment bolt, and the friction block is tiltable with respect to the small diameter end surface to follow the small diameter end surface of the bevel gear. A friction adjustment device for a bevel gear device in a vehicle steering system according to item 2. 4. The friction adjustment device for a bevel gear device in a vehicle steering system according to claim 1, wherein the first bearing is a thrust needle bearing, and the second and third bearings are ball bearings. .