JPS581296B2 - Vehicle disc brake - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a disc brake, and improves the smoothness of the sliding movement of the cam plate by improving the support method of the cam plate for pressing the disc in the braking direction. Another object of the present invention is to provide a disc brake for a vehicle that achieves increased cooling effect and reduced weight, reduces the number of parts, and promises a simplified structure and ease of processing.

Disc brakes are often used to brake the drive wheels of traveling vehicles such as tractors, but in conventional brakes, the cam plate that presses the disc in the braking direction has a cam plate that covers the entire outer circumferential surface or the inner circumferential surface of the disk. Since the brake case was slidably supported on the inner circumferential surface of the brake case or on the outer circumferential surface of an annular support member separately provided on the side wall of the vehicle body, a large amount of sliding capacity was required, and there was waste in manufacturing and cooling. There were significant deficiencies in terms of effectiveness and other aspects.

In other words, in the case of the so-called outer periphery support type in which the entire outer periphery of the cam plate is fitted and supported on the inner periphery of the brake case, the sliding area is the entire outer periphery, so it is necessary to ensure proper sliding. The entire area must be finished with a high degree of precision, and even if finished in this way, the sliding area would be large, so the operating force required to rotate the cam plate in the braking direction and slide it would be large. It has become.

Furthermore, even in the case of the so-called inner peripheral support type in which the inner peripheral surface of the cam plate is fitted and supported on the outer peripheral surface of an annular support member separately provided on the side wall of the vehicle body, the entire inner peripheral support surface becomes a sliding surface. There are the same problems as the outer periphery support type.

The present invention eliminates the deficiencies of the prior art by supporting the cam plate in divided support at predetermined intervals in the circumferential direction, and the specific structure thereof will be described in detail below with reference to the drawings.

In FIGS. 1 and 2, reference numeral 1 denotes a transmission case which is a part of the tractor body. In addition to storing lubricating oil, the case 1 also has a built-in differential device 2 and the like.

A bearing case 3 is attached to the side wall of the transmission case 1 with bolts 4 or the like, and supports the differential case 6 via a radial ball bearing 5.

Reference numeral 7 denotes a pair of left and right differential gear shafts extending outward from the differential gear 2, each of which has a differential side gear 9 that meshes with a differential pinion 8 at its inner end, and a final reduction gear at the outer end of the differential gear shaft 7. through which it is connected to the rear axle.

Reference numeral 10 denotes a brake disc having a lining on both sides of the radial circumference, and its inner circumferential surface engages with a spline 11 etc. formed in the middle of the differential gear shaft 7, so that it rotates together with the differential gear shaft 7 and It is attached to the outer region of the bearing case 3 so as to be freely slidable in the axial direction.

Reference numeral 12 denotes protrusions for ball receiving holes that protrude from the outer periphery of the flange portion of the bearing case 3 at predetermined intervals in the circumferential direction.
is stored so that it can roll freely.

In order to prevent the balls 14 from rolling and causing scratches on the outer surface of the side wall of the transmission case 1, the balls 14 and the case 1 are
An inclusion 15 made of resin, sheet metal, or the like and having a groove-shaped cross section is interposed between the outer surface and the outer surface.

Reference numeral 16 denotes a cam support stand protruding from the outer surface of the bearing case 3. As shown in the second figure, the cam support stands 16 are provided at predetermined intervals in the circumferential direction, and the outer circumferential surface of the support stand 16 is substantially It is a perfect circular arc surface centered on the axis of the differential gear shaft 7.

Reference numeral 17 denotes a cam plate having a cam groove 18 on the surface facing the ball 14 and a lever engaging groove 19 on a part of the outer periphery, and is fitted onto the cam support base 16 so as to be rotatable and movable in the axial direction. has been done.

That is, in the first and second illustrated examples, the cam plate 17 is illustrated as an inner peripheral support type.

The inner peripheral surface of the cam plate 17 has recesses 20 cut out at predetermined intervals in the circumferential direction as shown in the second figure.
Only the top surface of the convex portion 21 between 0 and 0 is a smooth surface 21a and is supported on the outer peripheral surface of the support base 16, and at this time, the cam plate 17 is rotated to press the disc 10 in the braking direction. Since the smooth surface 21a and the outer circumferential surface of the support base 16 do not come apart within the rotation range, the smooth surface 2
The length of the arcuate surface 1a in the circumferential direction is larger than that of the outer peripheral arcuate surface of the support base 16.

22 is a brake case consisting of a base 23 and a cover 24, and the base 23 is attached to the transmission case 1 with bolts 2.
5 etc., and the inner surface of the base 23 is substantially the braking surface 2.
6, therefore, the disc 10 is on the braking surface 2.
6 and the cam plate 17.

Reference numeral 27 denotes a lever support shaft attached to the base 23 of the brake case 22 so as to be rotatable around a horizontal axis, and a cylindrical boss portion 2 formed as an inwardly protruding shape is substantially formed in a part of the base 23.
8, and levers 29 and 30 are fixedly installed inside and outside of it, respectively.

The inner lever 29 is formed by bending a round bar into an L shape, and its free end is engaged with the engagement groove 19 of the cam plate 17, and one end of the brake rod 31 is attached to the outer lever 30 with a pin 32. It is pivotally connected.

Of course, the other end of the brake rod 31 is attached with an operating member such as a brake pedal.

To explain the operation of the embodiment of the present invention configured as described above, when the brake pedal or the like is depressed, the brake rod 31 moves in the direction of the arrow shown in the second figure, and the lever 29 moves around the lever support shaft 27 in the direction of the clock hand in the second figure. A force is applied to rotate the cam plate 17 in the counterclockwise direction.

Then, since the cam groove 18 is recessed in the cam plate 17 at a position facing the ball 14, the cam groove 18 is pressed while the ball 14 is rolling, and as a result, the cam plate 17 is moved to the disk as is known. 10 toward the braking surface 26, the disc 10 is held between the cam plate 17 and the braking surface 26, and the rotational force of the differential gear shaft 7 is braked.

In the above-mentioned operation, in the present invention according to the first and second illustrated examples, recesses 20 are formed on the inner circumferential surface of the cam plate 17 at predetermined intervals in the circumferential direction.
is formed, and the top surface of the protrusion 21 between the recesses 20, 20 is a smooth surface 21a, and this smooth surface 21a is supported by the outer peripheral surface of the support base 16, which is also formed at a predetermined interval in the circumferential direction. Therefore, the supporting area of the cam plate 17 does not cover the entire inner circumference, so the force required to rotate it is extremely small, and only the top surface of the convex portion 21 can be machined with high precision.
Precision casting is now possible, and production costs can be significantly reduced.

That is, the support stand 16 is integrally formed with the flange of the bearing case 3, and it is extremely easy to form the outer peripheral surface of the outer support stand 16 into a smooth surface coaxially with the axis of the differential gear shaft 7. The bearing case 3 supports the differential gear shaft 7 and the differential device 2, and also supports the cam plate 17.
Since it also serves as support for the parts, the number of parts can be reduced.

In addition, the fact that the support area of the cam plate 17 is divided and supported at predetermined intervals in the circumferential direction means that the sliding surface of the cam plate 17 is small, so the sliding movement of the cam plate 17 is made lighter, and accurate sliding movement is guaranteed. .

Furthermore, since the inner peripheral surface of the cam plate 17 is partially cut out to form the recess 20, the weight of the cam plate 17 can be reduced by the amount of the cut of the recess 20, and in this respect, the sliding force of the cam plate 17 is also reduced. In addition to being lighter in weight, this recess 20 can also be used as a passage for lubricating oil, which promotes the cooling effect of the brake and the ability to lubricate the sliding surface, further reducing the sliding force. promise.

The present invention is as described above, and according to the present invention, the entire inner circumference of the cam plate for pressing the disc in the braking direction is not in sliding contact with the fixed support surface, and the inner circumference or the outer circumference of the cam plate is not in sliding contact with the fixed support surface. Since the cam plate is partially slidably supported in the direction, its sliding area is small, and as a result, the sliding force of the cam plate is reduced, ensuring reliable sliding.

In addition, since it is a partial support, only the partial support surface needs to be made smooth, which can significantly reduce manufacturing costs, and recesses are formed between the partial support parts. Since this recess can be used as a passage for lubricating oil, it suppresses the heat generation of the brake and increases its durability, and since the lubricating oil spreads well over the sliding surface, the sliding force can be further reduced. The weight itself can be reduced by forming the notch, and the support base that partially supports the inner periphery of the cam plate is integrated with the flange of the bearing case that is fixed to the side wall of the vehicle body that supports the differential device and the differential gear shaft. This not only allows parts to be used for multiple purposes, simplifying the structure and making assembly easier, but also because the support base is integrally formed with the flange of the bearing case at intervals in the circumferential direction. Advantages include the ability to accurately and easily machine the outer circumferential surface into a smooth surface concentrically with the axis of the differential gear shaft.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, with FIG. 1 being a longitudinal sectional side view and FIG. 2 being a longitudinal sectional front view. 7... Rotating shaft (differential gear shaft), 10... Disc, 14
... Ball, 17 ... Cam plate, 18 ... Cam groove,
20... Concave portion, 21... Convex portion, 21a... Smooth surface, 16
...Support stand, 26...braking surface.

Claims (1)

[Claims] 1. In a vehicle disc brake in which a cam plate presses a disc in the braking direction to brake a differential gear shaft, a bearing case that rotatably supports the differential device is attached to the side wall of the vehicle body, and a flange of the bearing case is attached to the flange of the bearing case. Support stands are integrally formed to project at intervals in the circumferential direction, each of the outer circumferential surfaces of the support stands are formed as a smooth surface on a circumference coaxial with the axis of the differential gear shaft, and the inner circumferential surface of the cam plate is A cam plate is fitted onto a support base so that a smooth surface corresponding to the smooth surface is formed, and both smooth surfaces are slidably slidable in the axial and circumferential directions. A vehicle disc brake characterized by having a radially outward concave portion formed on an inner circumferential surface.