JPS61233230A - Piston structure for hydraulic brake - Google Patents

Abstract

PURPOSE:To reduce the size of hydraulic brake by forming the piston of hydraulic brake into top-hat type while utilizing the drum section as the guide face is for the cylinder and the flange section stretching from the drum section as the pressurizing face of brake disc. CONSTITUTION:A top-hat type piston 29 is contained in the hydraulic cylinder 25 of hydraulic brake. The drum section of piston 29 is utilized as the guide face for the cylinder 25 while the flange section 31 stretching from the drum section is utilized as the pressurizing face of brake disc 18. Since the piston 29 has simple shape and short axial length, the size of hydraulic brake can be reduced considerably.

Description

[Detailed description of the invention] The present invention relates to a piston structure for a hydraulic brake.

Hydraulic brake systems, which are almost maintenance-free, have recently been adopted in small tractors as well, but the piston structure that pushes the brake discs is
For example, Utility Model Application No. 58-31438, No. 58-31448
A ring-shaped piston, such as that seen in No. 1 and No. 58-50321, is common.

However, in such a ring form, the pressure receiving area ratio between the brake piston and the piston in the master cylinder is extremely large, and the slide stroke length is also relatively small compared to the diameter dimension of the brake piston. Because of this, the sliding movement is biased,
The braking effect tends to be unstable, and the braking effect is poor, and it is not possible to secure a sufficient gap between the brake discs when the brake disc releases and returns. It is clear that this becomes more and more difficult as the brake disc is made up of multiple discs.

The present invention is intended to improve these problems, and its specific configuration will be described in detail based on the illustrated embodiments as follows. That is, Fig. 1.2 shows a hydraulic brake system, where (lO) is the tractor body, and (11) is the master cylinder that is operated by pressing the pedal (12) from above the cockpit. It is connected to a brake hydraulic cylinder, which will be described later, via a pressure oil supply and discharge pipe (13). The system of the conduit (13) is in an immovable state and can be freely buried inside the tractor body (lO), so the leg area of the cockpit is secured as wide as possible, and the space above the seat is When installing a cabin etc., there will be no restrictions on space.

(A) is the center case of the tractor body (10), and as is clear from the enlarged view in Fig. 2, the center part houses the mission mechanism (not shown) and the built-in chamber (a) of the differential gear (14). ), the cross section is divided into a U-shape, and
Similarly, the adjacent sideways position is achieved by the partition wall (15) as a reduction gear built-in chamber (b) with a rectangular cross section. The opening surface of the built-in chamber (b) substantially corresponds to the opening surface of the axle case (B) so that it can be joined to the opening surface of the axle case (B). (16) is a differential gear shaft that extends outward from the differential case (17) of the differential gear (14) in a horizontally suspended state, and its projecting end extends beyond the built-in chamber (b) and extends from the axle case (17).
B), and a so-called multi-plate brake disc (18) is spline-fitted to the protruding end thereof.

(19) is a differential bearing case fitted to the partition wall (15) of the center case (A), and the intermediate portion of the differential gear shaft (16) is also supported by the bearing (20). (21) is the fixing bolt for the differential bearing case (19), and (22) is the axle case (B).
The axle is supported at the lower position of the axle, and is maintained horizontally in two stages parallel to the differential gear shaft (16), above and below. 23) By the meshing of (24), they are linked to freely decelerate and rotate. Both reduction gears (23) (24)
It is clear from the diagram that the main body is housed in the built-in chamber (b) of the center case (A).

Also, (25) is a hydraulic cylinder that is formed integrally and continuously overhanging the upper part of the axle case (B), and has an opening so as to face the brake disc (18) on the differential gear shaft (16) so as to be substantially in the same position. has been done. (
26) is a sealing material fitted to the inner peripheral surface of the sealing material, (27)
) is the air bleed plug, and its hydraulic cylinder (2
Needless to say, in 5), the above-mentioned brake pressure oil conduit (13) is opened for communication. In that case, in the illustrated example, the hydraulic cylinder (25) is connected to the axle case (B) as a part of itself, but instead, as shown in Figure 3, the hydraulic cylinder (25) is connected to the axle case (B).
B), and the installation port (2) of the axle case (B).
8) It may be fixed by fitting it into a lid shape.

In any case, the hydraulic cylinder (25) contains a brake piston (2) that pushes the brake disc (18).
9) is enclosed, and its hydraulic pressure causes the pedal (12) to
The braking force proportional to the pedal pressure on the brake disc (18)
It is now granted to The brake piston (29) has a top-hat type or a cylinder-hat type that substantially corresponds to the hydraulic cylinder (25), and its body (30) serves as a sliding guide surface for the hydraulic cylinder (25) and also as a cylinder hat type. The flange portion (31) that continuously protrudes from the portion (30) is the brake disc (18).
They are designed vertically so that they each function as a pressure surface for the pressure receiving surface.

As long as this function can be achieved, the brake piston (29) is attached to the flange (29) as shown in Fig. 3.4.
31) with a solid body (30) or a top surface of the body (30) (32), it is possible to assemble another body plate (33) in a laminated manner. Although it is possible to manufacture it by various methods, it is possible to make it into a generally uniform thickness as shown in Fig. 2 by pressing a steel plate or other plastic working, and also to make the thickness flexible. In the case where the device is made as thin as possible, it is preferable to adopt the configuration shown in FIG.

That is, the flange (31) is arranged such that the protruding base end position (P1) of the flange (31) is further away from the pressure receiving surface of the brake disc (18) by a certain distance than the tip position (P2).
) is given a certain inclination angle (θ) in advance so as to intersect with the pressure receiving surface of the brake disc (18), so that when the brake disc (18) is substantially braked to its maximum. Then, as shown in Fig. 6, an elastic deformation effect is generated at the proximal end position (Pl) of the flange (31), so that its pressure-applying surface is completely brought into close contact with the pressure-receiving surface of the brake disc (18). stipulated in The top surface of such a brake piston (29) is also preferably curved in a convex shape that projects slightly outward as shown in the figure.

As mentioned above, when the flange (31) that serves as the pressurizing surface of the brake disc (18) is made flat by plastic working from a steel plate as thin as possible, when the brake piston (29) receives hydraulic pressure during use, The protruding base end position (Pl) of the flange (31) close to the action center line (Y) pushes the brake disc (18) excessively, while the protruding tip position (P2) pushes the brake disc (18) too much. A phenomenon that causes a shortage of power will occur. In this point,
The above configuration has been described as suitable because it can eliminate such braking defects. The above inclination angle (θ
) is, of course, selected to be an appropriate value in advance in anticipation of excesses and deficiencies in such phenomena.

Furthermore, the reference numeral (34) in FIG. 2 indicates a brake piston (29).
) is a partition plate that sandwiches the brake disc (18) on the differential gear shaft (16). It is inserted between the joint of the opening surface and the opening surface of the axle case (B), and is installed in the center case (
To attach the axle case (B) to A), use the bolts (35
), and are fastened and fixed at the same time. Then, due to the interposition of the flat partition plate (34), the built-in chambers (
b) is also completely covered, and its built-in chamber (b)
The hydraulic cylinder (25) and the hydraulic cylinder (25) are also separated from each other. However, due to its function, the oil for dissipating the frictional heat of the brakes convects between each chamber through the oil communication ports (sl) and (s2) formed in the partition plate (34) and the partition wall (15), respectively. Needless to say, it has become like this.

This partition plate (34) is connected to a midway support bearing (
36) It also serves as the case for (37), and its long axle (22) is supported not only by this bearing (37) but also by bearings (38) and (39) at both its inner and outer ends. Not only is the stability of the assembled state excellent, but also the assembly work can be carried out efficiently by using the above-mentioned POL (35). The support bearing (38) at the inner end thereof is fitted into the partition wall (15), and is prevented from being removed by a retaining plate (40). (41) is the fixing bolt of the holding plate (40), (4
2) is a collar, (43) is a sealing material, and needless to say, a wheel (44) is attached to the outer end of the axle (22) extending from the axle case (B).

As described above, in the present invention, the hydraulic brake piston (
29) is formed into a top hat shape or cylinder hat shape as a whole, and its body (3o) serves as a slide guide surface for the hydraulic cylinder (25), and a flange that continuously projects from its body (30). (31) are respectively set as pressurizing surfaces for the brake disc (18), so the conventional problems mentioned at the beginning can be reliably solved, and despite the simple overall structure, Therefore, excellent braking effect can be obtained.

In other words, compared to known ring-shaped pistons, its overall top hat or cylinder hat form makes it possible to secure a longer slide stroke length with respect to the diameter dimension, and the pressure receiving area ratio with the master cylinder (11) is also increased. Since it can be set appropriately small and rationally, it is possible to not only secure a stable gap for the multi-plate brake disc (18) when the brake is released, but also
A high-performance braking effect is also achieved.

In particular, the flange (
31) is given the above-mentioned constant inclination angle (θ) in advance, and the central flange (31) of the brake piston (29) is
) by causing an elastic deformation action such as a so-called disc spring, so that the flange (31) is brought into close contact with the brake disc (18) as a whole, the above effect can be further improved. Not only is this possible, but it is also possible to absorb unevenness on the pressure-applying and pressure-receiving surfaces.
Furthermore, the brake piston (29) as a whole can be easily plastic-processed from a thin steel plate, which is extremely useful for mass production.

[Brief explanation of drawings]

Fig. 1 is an overall schematic side view showing the operating system of the hydraulic brake according to the present invention, Fig. 2 is an enlarged sectional view of the main parts of the device, and Fig. 3 is a sectional view showing a partial modification of Fig. 2. , FIG. 4.5 is an enlarged semi-cutaway sectional view showing various modifications of the piston, and FIG. 6 is an enlarged half-cutaway sectional view corresponding to FIG. 5, showing the operating state of the brake. (A) ...Center case (B) ...Axle case (θ) ...Inclination angle (18) ...Brake disc (25) ...Hydraulic cylinder (29)... Brake piston (30)... Body (31)... Tsuba Patent applicant Kenji Yamashita, Patent attorney Toyosha Co., Ltd...., ■" Figure 3 Figure 5 Procedural amendment document April 10, 1985 Patent application filed on April 4, 1986 (4) 2, Title of invention Piston structure of hydraulic brake 3, Person making the amendment Case and Relationship: Patent applicant: 1°6-55 Jyojo Teramachi, Kadoma City, Osaka Prefecture Toyosha Co., Ltd. 4, Agent 6, Specification to be amended (detailed description of the invention and brief description of drawings) 7. Amendment Contents (1) On page 2, line 10 of the specification, the phrase "small tractor" is corrected to "small tractor and other vehicles." (2) On page 3 of the same book, lines 9 and 10, it says, ``Figure 1.2 represents 11-----・-----1.''
``Figure 1.2 shows an example of a hydraulic brake system commonly used on tractors.'' I am corrected. (3) In the first line of page 10 of the same book, the phrase "Needless to say." Of course, the present invention can also be applied in the same way.'' (4) In the same book, page 11, line 14, the statement ``Figure 1 shows the present invention'' is corrected to ``The figure illustrates the present invention adapted to a tractor, and Figure 1 is the same.'' (5) In the drawings, Figure 5 will be corrected as shown in the attached sheet. Figure 5

Claims (1)

[Claims] 1. The entire body is formed into a top hat shape or a cylinder hat shape, and the body (30) is used as a slide guide surface for the hydraulic cylinder (25), and the body (30) is formed as a slide guide surface for the hydraulic cylinder (25).
A piston structure for a hydraulic brake, characterized in that a flange (31) that continuously protrudes from a flange (30) is set as a pressurizing surface for a brake disc (18). 2. Place the brake disc (18) on the pressure receiving surface of the brake disc (18) so that the protruding base end position (P1) of the flange (31) is further away from the pressure receiving surface of the brake disc (18) by a certain distance than the tip position (P2). A certain inclination angle (θ) intersecting with the pressure-receiving surface is provided in advance, and the elastic deformation of the flange (31) that occurs during disc braking brings the pressure-applying surface into close contact with the pressure-receiving surface as a whole. A piston structure for a hydraulic brake according to claim 1, characterized in that the piston structure is set as follows. 3. A piston structure for a hydraulic brake according to claim 1, characterized in that the steel plate is bent into a top hat shape or cylinder hat shape with substantially uniform thickness as a whole by plastic working.