JPH0358933B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a hydraulic brake device useful for use in small tractors, forklifts, and other various vehicles.

<Conventional technology and its problems> For example, small tractors generally use a dry internal expansion type brake system, but in this model, the link mechanism such as the brake rod that makes up the operation system is complicated and moved outside the brake case. Not only does it look unsightly and is extremely troublesome to inspect and maintain, it is also difficult to provide a simple and wide space for the cockpit area, and it is also difficult to install the cabin and other layouts.
There is a problem with the design being constrained.

On the other hand, the wet type (oil immersion type) brake equipment that was developed later can be said to be beneficial in that maintenance is free, but the operation of the brake disc has been discussed, for example, in Japanese Utility Model Application No. 57-91655. No. 58-106630, No. 58-12726, JP-A-58-
Most of these are done using ball cams or other mechanical actuators, as seen in No. 72730.

Therefore, in addition to the brake disc, a large number of operating parts and high precision machining are required, and the brake system as a whole is still complex and large. I can't say that.

<Means for Solving the Problems> The present invention contemplates a fundamental solution to these problems, and for this purpose, a differential gear shaft that is sent out from a differential device built in a center case,
The axles protruding from the axle case attached to the center case are kept in a parallel horizontal structure with upper and lower stages, and a brake disc is fitted to the protruding end of the differential gear shaft, and both axles are connected to the reduction gear. In vehicles such as tractors in which the axles are connected to each other so that they can decelerate and rotate freely through meshing, the hydraulic cylinder for enclosing the brake piston that provides braking force to the brake disk has an opening that faces substantially concentrically with the brake disk. The hydraulic cylinder is installed in a part of the case, and the master cylinder, which is operated by pressing a pedal from above the driver's seat of the vehicle, is communicated and connected by a brake oil supply and discharge pipe, and the hydraulic cylinder is A brake cover of a size capable of sandwiching the brake disc together with the protruding flange of the tophat-type brake piston enclosed in the brake piston is arranged and fixed so as to substantially face the mounting plane of the center case and the axle case, and It is characterized in that a braking force proportional to the pedal pressure is applied to the brake disc only by the hydraulic pressure supplied into the hydraulic cylinder.

<Example> Hereinafter, the specific configuration of the present invention will be described in detail based on the illustrated example. Figures 1 and 2 show the hydraulic brake device of the present invention applied to a small tractor, and 10 is a vehicle body. , 11 is a master cylinder which is operated by pressing a pedal 12 from above the cockpit, and is connected to a brake hydraulic cylinder to be described later through a brake pressure oil supply/discharge pipe 13.

The entire supply/discharge pipe 13 remains stationary and can be freely buried inside the vehicle body 10, so that the leg area of the cockpit can be simply and as wide as possible, and the seat When constructing a cabin or the like, there are no restrictions on the installation space.

Reference character A is the center case of the vehicle body 10, and as is clear from the enlarged view in FIG. In addition, the horizontal position adjacent to the center is partition wall 1.
5, it is connected as a reduction gear built-in chamber b which opens outward and has a substantially U-shaped cross section.

Reference numeral 16 denotes a differential gear shaft that extends outward from the differential case 17 of the differential device 14 in a horizontally extending state, and its projecting end is slightly further away from the mounting plane L-L between the center case A and the axle case B. The brake disc 18 is extended to an outward position, and a brake disc 18 is spline-fitted to such a projecting end.

19 This is a differential bearing case fitted into the partition wall 15 of the center case A, and the intermediate portion of the differential gear shaft 16 is also supported by its bearing 20. Numeral 21 is a bolt for fixing the differential bearing case 19 to the partition wall 15 from the outside.

The axle case B has an opening face that faces the opening face of the reduction gear built-in chamber b, which has a substantially U-shaped cross section in the center case A, and the opening face is located on the mounting plane L-L when the reduction gear built-in chamber b is located. is joined from the outside to the opening surface of the mounting bolt 22.
It is fixed by. The lower part of the axle case B has a cylindrical shape that encloses the axle 23 and extends laterally outward.

The axle 23 is parallel to the differential gear shaft 16 in two horizontal stages, upper and lower, and both shafts 16, 2
By meshing the reduction gears 24 and 25 on 3, they are linked to rotate at a reduced speed. In other words, the reduction gear built-in chamber b of the center case A
In this case, the small-diameter gear 24 that integrally projects from the midway portion of the differential gear shaft 16 and the large-diameter gear 25 that is spline-fitted to the corresponding position on the axle 23 are maintained so as to constantly mesh and rotate. be.

A bearing 26 supports the small-diameter inner end of the axle 23, and is fitted into the partition wall 15 of the center case A, and is prevented from coming off by a retaining plate 27. 28 is a fixing bolt for the holding plate 27; 29 is a bearing fitted to the axle case B to support the outer end of the axle 23; 30 is a sealing material; 31 is a collar;
Needless to say, the axle 32 is attached to the protruding flange of the axle 23 extending laterally outward from the axle case B.

Further, s is a cylinder mounting port opened at the upper part of the axle case B, where a hydraulic cylinder 33 with an opening that faces substantially concentrically with the multi-plate brake disc 18 on the differential gear shaft 16 is installed.
is fitted and integrated with the lid closed. 34
is a retaining ring fitted to the outer peripheral surface of the hydraulic cylinder 33, and 35 and 36 are sealing materials respectively fitted to the outer peripheral surface and the inner peripheral surface, and by the sealing material 36 on the inner peripheral surface, brake piston 3
It is maintained in an oil-tight condition with 8.

In that case, although the hydraulic cylinder 33 is shaped like a top hat with the flange 37 protruding from the opening edge in the illustrated example, the shape may be other than the above as long as the sliding stroke length of the brake disc 18 can be maintained constant. It may be formed into various shapes.

Further, as long as the brake disc 18 can be received while being located at the upper part of the axle case B, the hydraulic cylinder 33 itself can be formed as a continuous integral part with the axle case B, projecting out as shown in FIG. It is. In any case, the brake pressure oil supply/discharge pipe 13 is connected to the top surface of the hydraulic cylinder 33 exposed from the axle case B. Incidentally, the reference numeral 39 in FIG. 3 indicates an air bleed plug.

The brake piston 38 is the hydraulic cylinder 3
The body 40 functions as a slide guide surface for the hydraulic cylinder 33, and the flange 41 protruding from the body 40 functions as a pressurizing surface for the brake disc 18. The brake disc 18 can be pushed by hydraulic pressure fed into the hydraulic cylinder 33.

Since the brake disc 18 is shaped like this top hat, although it is small and flat as a whole, it is possible to ensure as long a slide stroke length as possible for its diameter dimension.
Furthermore, even when the cylinder 33 slides, the body 40 forms a slide guide surface with the cylinder 33, so it never becomes an incorrect biased posture, and can be operated stably and efficiently at all times. Brake disc 1 at time
Therefore, the braking effect on the multi-plate brake disc 18 is particularly excellent.

Furthermore, 42 is a brake cover that can sandwich the brake disc 18 on the differential gear shaft 16 in conjunction with the protruding flange 41 of the top-hut type brake piston 38, and forms a pressure receiving surface of the brake disc 18 that corresponds to the pressure applying surface. Therefore, it is shaped to have substantially the same size as the brake disc 18.

Moreover, the brake cover 42 is arranged and fixed so as to substantially face the mounting plane L-L between the center case A and the axle case B, and the bearing 43 that stably supports the midway portion of the differential gear shaft 16 is fixed. It is defined so that it can function as a case as well.

In this regard, in the illustrated example, when positioning and fixing the brake cover 42 so as to substantially face the mounting plane L-L, it is joined to the opening surface side of the axle case B,
In addition, the brake installation chamber c, which is fixed with bolts 44 and partitioned by the brake cover 42 and the hydraulic cylinder 33, is finished as a unit body in advance, but in contrast to this, the brake cover 42
may be joined and fixed to the opening side of the center case A.

In any case, the brake cover 42 is located on the mounting plane L-L between the center case A and the axle case B, and is disposed perpendicularly to the differential gear shaft 16, so that the bearing 43 As a result, the middle part of the differential gear shaft 16 can be stably and rationally supported, and the reduction gear built-in chamber b and the brake installation chamber c are separated from each other by the brake cover 42 due to the support structure. Become.

However, it goes without saying that the oil to release the frictional heat generated during the braking action of the brake disc 18 is designed to convect between the two chambers b and c. Reference numeral 45 indicates an oil communication port between the reduction gear built-in chamber b and the differential gear built-in chamber a.

Although the present invention has been described above as a hydraulic brake device applied to a tractor, it goes without saying that the present invention can be similarly applied to forklifts and other various vehicles.

<Effects of the Invention> As described above, the hydraulic brake device of the present invention has a structure in which the differential gear shaft 16 comes out from the differential device 14 built in the center case A, and the axle shaft attached to the center case A. The axle 23 protruding from the case B is maintained in a horizontally parallel state with two upper and lower stages, and the brake disc 18 is fitted to the protruding end of the differential gear shaft 16.
3 is connected to the axle 2 by the meshing of the reduction gears 24 and 25.
In particular, in the vehicle such as a tractor which is connected to allow deceleration and rotation as described in No. 3, the hydraulic cylinder 33 for enclosing the brake piston 38 that applies braking force to the brake disc 18 is configured to have an opening facing substantially concentrically with the brake disc 18. As, axle cake B
The hydraulic cylinder 33 and the master cylinder 11, which is operated by pressing the pedal 12 from above the driver's seat of the vehicle, are connected to the brake oil supply and discharge pipe 13.
The overhanging flange portion 4 of the tophat-type brake piston 38 enclosed in the hydraulic cylinder 33 is
A brake cover 42 having a size that can sandwich the brake disc 18 together with the brake cover 18 is arranged and fixed so as to substantially face the mounting plane L-L between the center case A and the axle case B. Since it is determined that a braking force proportional to the depression pressure of the pedal 12 is applied to the brake disc 18 only by the hydraulic pressure supplied to the brake disc 18, the problems of the prior art described at the beginning can be completely solved. I can do it.

That is, the means for applying braking force to the brake disc using the well-known ball cam or other mechanical actuator mentioned at the beginning requires a large number of differential parts, and the machining accuracy of the differential parts is high. If there are variations in assembly accuracy or assembly accuracy, the reliability of brake performance will decrease, but in the case of the present invention, the differential movement of the brake disc 18 is performed only by hydraulic pressure, and the When the pedal 12 is depressed, a braking force proportional to the pedal pressure is efficiently applied to the brake disc 18 through the sliding action of the brake piston 38, so that an appropriate precision effect with no variation is always obtained. This has the advantage that the brake performance is excellent in reliability, and that the required configuration is extremely simple and sufficient.

Further, since the hydraulic cylinder 33 for enclosing the brake piston 38 is partially installed in the axle case B in an open form facing the brake disc 18 on the differential gear shaft 16 substantially concentrically, the axle case B The entire brake system can be compactly and rationally incorporated while making effective use of and pedal 12
The piping between the master cylinder 11 and the master cylinder 11, which is operated by foot pressure, can be done in an extremely simple system in a space-saving manner, and there are no design restrictions when installing the cabin or performing other layouts. .

Furthermore, the brake piston 38 is shaped into an overall top-hat shape, with its protruding flange 41 serving as the pressurizing surface of the brake disc 18, and the body 40 also supports the hydraulic cylinder 33.
The brake cover 4 is designed to slide correctly and is large enough to sandwich the brake disc 18 together with the projecting flange 41.
2 is arranged and fixed on the mounting plane L-L between the center case A and the axle case B, which not only significantly increases the assembly rigidity of the brake device, but also prevents the brake piston 38 from sliding in an incorrect position. No movement occurs, and an even pressing braking force can be applied to the brake disc 18 at all times.

In particular, when placing and fixing the brake cover 42 on the mounting plane L-L between the center case A and the axle case B, if it is fixed to the opening side of the axle case B with bolts 44, the brake cover The brake piston 38 and the brake disc 18 are installed in advance into the brake installation chamber c divided by the hydraulic cylinder 42 and the hydraulic cylinder 33, and the axle case B, which has been assembled into a unit, is transferred to the center case A for deceleration. By joining and fixing the gear built-in chamber b in the closed state, both cases A and B can be assembled extremely easily.

In that case, if the brake cover 42 is also used as a bearing case and the midway portion of the differential gear shaft 16 is supported via the bearing 43 fitted thereto, the assembly rigidity of the brake device can be further increased. At the same time, the brake disc 18 fitted to the protruding end of the differential gear shaft 16 can be kept more stable, so the braking action by the brake piston 38 becomes extremely smooth, which can be said to be of great practical benefit.

[Brief explanation of drawings]

The figures relate to an embodiment of the present invention applied to a tractor, in which Fig. 1 is an overall schematic side view showing the operating system of the hydraulic brake device, and Fig. 2 is a sectional view similarly showing an enlarged main part of the brake device. FIG. 3 is a sectional view showing a partial modification of FIG. 2. A...Center case, B...Axle case, L
-L... Mounting plane, 10... Vehicle body, 11... Master cylinder, 12... Pedal, 13... Supply/discharge pipe, 14... Differential device, 16... Differential gear shaft,
18...Brake disc, 23...Axle, 2
4, 25... Reduction gear, 33... Hydraulic cylinder, 38... Brake piston, 41... Overhanging flange, 42... Brake cover, 43... Bearing, 44... Bolt.

Claims (1)

[Claims] 1 Differential device 14 built in center case A
The differential gear shaft 16 extending from the center case A and the axle 23 extending from the axle case B attached to the center case A are maintained in a horizontally parallel state with two upper and lower stages, and a brake disc 18 is attached to the extending end of the differential gear shaft 16. At the same time, the above-mentioned both shafts 16, 2
3 is connected to the axle 2 by the meshing of the reduction gears 24 and 25.
In a vehicle such as a tractor that is connected to the vehicle such as No. 3 so as to be able to freely decelerate and rotate, a hydraulic cylinder 33 for enclosing a brake piston 38 that provides braking force to the brake disc 18 is provided.
is provided in a part of the axle case B as an opening facing substantially concentrically with the brake disc 18, and the hydraulic cylinder 33 and the master cylinder 11 which is operated by pressing the pedal 12 from above the driver's seat of the vehicle. , brake pressure oil supply and discharge pipe 13
The overhanging flange portion 4 of the tophat-type brake piston 38 enclosed in the hydraulic cylinder 33 is
A brake cover 42 having a size that can sandwich the brake disc 18 together with the brake cover 18 is arranged and fixed so as to substantially face the mounting plane L-L between the center case A and the axle case B. A hydraulic brake device characterized in that a braking force proportional to the depression pressure of the pedal 12 is applied to the brake disc 18 only by the hydraulic pressure supplied to the brake disc 18. 2. The hydraulic cylinder 33 is made as a separate object from the axle case B in a top-hat shape that substantially corresponds to the brake piston 38, and then fitted into the cylinder mounting hole s provided in a part of the axle case B in a closed state. The first aspect of the claims is characterized in that the brake pressure oil supply and discharge pipe 13 is connected to the top surface of the hydraulic cylinder 33 exposed from the axle case B. Hydraulic brake system. 3 Connect the hydraulic cylinder 33 to the brake piston 38
As a top hat type substantially corresponding to the above, it is formed so as to extend continuously and integrally from a part of the axle case B, and the supply and discharge pipe 13 for brake pressure oil is connected in communication with the projecting top surface of the hydraulic cylinder 33. A hydraulic brake device according to claim 1, characterized in that: 4. While making the brake cover 42 double as a case for the bearing 43 that supports the differential gear shaft 16, and positioning the brake cover 42 on the mounting plane L between the center case A and the axle case B,
Claim 1, characterized in that it is fixed to the opening surface side of the axle case B with bolts 44.
Hydraulic brake device as described in section.