JPH0554832U - Wet disc brake device - Google Patents

Abstract

(57) [Abstract] [Purpose] In a wet type disc brake device having a structure in which a mating plate is non-rotatably supported, a brake is easily released with a simple structure. [Structure] One of the facing surfaces of the pressure plate 5 and a mating plate 4 adjacent to the pressure plate 5 is formed as an uneven surface 7 that reduces the contact area between these surfaces by an appropriate amount.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a wet type disc brake device which is widely used in vehicles such as tractors.

[0002]

[Prior Art]

 At least one friction plate supported by the braked rotation shaft and at least two mating plates supported by the brake case are provided alternately, and the pressure plate facing the mating plate at one end is rotationally displaced. The wet plate brake device, which is operated to press the pressure plate by the cam means to frictionally engage the friction plate and the mating plate to obtain braking of the braked rotary shaft, regulates the mating plate. There are a structure that rotatably supports within a specified range and a structure that non-rotatably supports a mating plate. In the former structure, if all the mating plates are simply supported so as to be rotatable within a regulated range, the pressure from the mating plate that is about to be rotated by the friction plate in the engaged state with the friction plate is assumed. The servo effect of increasing the pressing force of the cam means by the rotational torque exerted on the plate is exerted greatly when the braked rotation shaft rotates in one direction, and the braking force is greatly increased in the same direction, whereas the braked rotation When the shaft rotates in the other direction, the braking force decreases by a corresponding amount, which causes a large imbalance in the braking force depending on the rotating direction, and therefore the braking force also increases depending on the rotating direction of the braked rotating shaft. Change. For this reason, as disclosed in Japanese Utility Model Publication No. 60-35805, the support structures of a part of the mating plate and the remaining mating plate are made different to reduce the imbalance of the braking force and the brake operating force depending on the rotation direction. An engineer who does is proposed. On the other hand, in the latter structure described above, since the mating plate is non-rotatably supported, the servo effect does not occur, and the braking force and the brake operating force are not imbalanced depending on the rotation direction (for example, the actual opening Sho 57-150636). (See the official gazette). The former type of brake device that exerts the servo effect has the advantage that the braking force in the forward direction of the vehicle can be increased by an appropriate amount than the braking force in the reverse direction by utilizing this effect. It is unavoidable that the structure is complicated by the mating plate support structure for reducing the unbalance, and in this respect, the latter brake device is often adopted as a simple structure.

[0003]

[Problems to be solved by the device]

 However, conventionally, a wet disc brake device having a structure in which a mating plate is non-rotatably supported has been found to have a difficulty in a brake releasing operation. That is, in the braking state, the friction plate and the companion plate are pressed against the pressure receiving surface of the brake case as a whole, and the rotary shaft braking is performed under the condition that the friction plate, the mating plate, and the pressure receiving surface are elastically deformed. However, in this braking state, the mating plate on one end and the pressure plate are in close contact with each other on smooth surfaces. As it can be understood from the fact that it is extremely difficult to shift and separate two superposed glass plates from each other, close contact between smooth surfaces is a so-called adsorption phenomenon, and separation of the pressure plates is extremely difficult. It will be. It may be considered that the oil in the brake case makes it easier for the mating plate and the pressure plate to slip, and assists the separation, but the oil conversely fills the gap due to some elastic deformation of the mating plate. Just as it is more difficult to separate the two glass plates that have been smoothed and water-wetted, it promotes the adsorption phenomenon and makes it more difficult to separate the pressure plate. In the above-mentioned Japanese Utility Model Application Laid-Open No. 57-150636, the pressure plate is forcibly rotationally displaced in both the brake actuating direction and the brake releasing direction by the operating means. From the above point, however, the pressure plate is in the brake releasing direction. It is recognized that the brake release operation to rotate and displace is heavy. Further, for example, as disclosed in Japanese Utility Model Laid-Open No. 59-62334, as a simpler operating means, rotational displacement of the pressure plate in the brake actuating direction is forcibly generated, but simply operating means is provided in the braking releasing direction. There is also a method in which the pressure plate is separated by the restoring force from the elastically deformed state of the friction plate and the mating plate only by separating it from the pressure plate, but a situation in which braking release cannot be achieved by such operating means may occur. ..

Therefore, an object of the present invention is to eliminate the above-mentioned difficulty in releasing the braking of a wet type disc brake device of a type that non-rotatably supports a mating plate with a simple structure.

[0005]

[Means for Solving the Problems]

 Therefore, the present invention, as illustrated in FIGS. 2 and 3, includes at least one (two in the illustrated example) friction plate 2 and a brake case which are slidably supported on the braked rotary shaft 1 and cannot rotate relative to each other. At least two (three in the illustrated example) mating plates 4 slidably and non-rotatably supported on the brake case 3 are alternately arranged, while the brake case 3 is rotatably and slidably supported on the operating means. A pressure plate 5 which is rotationally displaced by means of the pressure plate 5 is provided facing the mating plate 4 at one end, and the pressure plate 5 and the brake case 3 are operated by the rotational displacement of the pressure plate 5 to rub the pressure plate. The following means were taken in the wet type disc brake device provided with the cam means 6 for pressing the plate and the mating plate.

That is, in the present invention, as illustrated in FIGS. 1 and 4, respectively, one of the surfaces of the pressure plate 5 and the mating plate 4 at one end facing each other is defined as one of these surfaces. It is formed on the uneven surface 7 that reduces the contact area between them by an appropriate amount. Further, the present invention also proposes to provide the concave portion 7a of the concave-convex surface 7 so that the concave portion 7a always opens in the brake case 3 as illustrated in FIGS. 1 and 4, respectively. (Claim 2).

[0007]

[Action]

 It was tested that if the contact surface area between the pressure plate 5 and the mating plate 4 adjacent to it by the uneven surface 7 is positively reduced as compared with the case of smooth surfaces, the braking release of the brake becomes much easier. As a result, I found. Although the reason for this is not completely understood, the above-mentioned surface portions that are attracted to each other between the pressure plate 5 and the mating plate 4 are reduced, and if it is a smooth surface, a continuous oil film is formed to form a space between the two surfaces. It is judged that the oil that resists relative movement can move freely in the recesses on the discontinuous uneven surface and acts as a lubricant between the two surfaces. If the concave portion 7a of the concave-convex surface 7 is always opened in the brake case 3, the oil is not confined between the two surfaces, and the relative movement between the pressure plate 5 and the mating plate 4 becomes easier. Become.

[0008]

【Example】

 In FIG. 2, reference numeral 11 represents a mission case of the work vehicle, and the brake case 3 which is supposed to be covered with a case lid 3a is integrally formed on the outer surface of the mission case 11. In FIG. 3, reference numeral 12 denotes a bolt for attaching the case lid 3a. As shown in FIG. 2, the braked shaft 1 projects from the inside of the transmission case 11 into the brake case 3.

As shown in FIGS. 2 and 3, a spline 1a is engraved on the braked rotary shaft 1, and two friction plates 2 in the illustrated example have a claw projecting at the inner peripheral end thereof engaged with the spline 1a. As a result, the rotary shaft 1 is supported so as to be slidable and non-rotatable relative to each other. The three hand plates 4 in the illustrated example are slidable and rotatable on the brake case 3 by fitting the protrusions 4a protruding on the outer peripheral end into the engagement grooves 13 on the inner peripheral surface of the brake case 3 in a fitting manner. It is imperatively supported. A pressure receiving surface 14 is formed on the inner surface of the brake case 3, the counter plate 4 at the inner end faces the pressure receiving surface 14, and the mating plate 4 at the outer end faces the pressure plate 5. In the pressure plate 5, a central cylindrical boss portion 5a is fitted to a support cylindrical portion 15 on the inner surface of the case lid 3a, and is supported by the brake case 3 in a rotatable and slidable manner.

The cam means 6 has a ball 6a whose half portion is fitted and supported in a concave groove 10 on the inner surface of the case lid 3a, and a plurality (three) of each ball 6a are provided. On the half side, it faces the inside of the cam groove 6 b provided in the pressure plate 5. As is well known, the cam groove 6b is formed as an inclined groove that is shallower in depth in one direction in the circumferential direction of the pressure plate 5. The operating means for rotationally displacing the pressure plate 5 is provided with an operating shaft 17 which is supported by the case lid 3a and extends over the inside and outside of the brake case 3. A brake arm 18 is attached to the outer end of the operating shaft 17. Further, the inner end portion is formed as a substantially semicircular integral cam 17a. As shown in FIGS. 1-3, the pressure plate 5 has an actuating protrusion 5b projecting toward the cam 17a, and the angular end face of this actuating protrusion 5b is engaged with the cam 17a. When the brake arm 18 is rotated in the direction of arrow A in FIG. 3, the cam 17a is rotationally displaced as shown by a chain line, and the cam 17a is pushed to displace the operating projection 5b as shown by a chain line. The pressure plate 5 is rotationally displaced in the direction of arrow B in FIG. Then, depending on the rotational displacement of the pressure plate 5, the ball 6a relatively moves from the deep portion to the shallow portion of the cam groove 6b, thereby pressing the pressure plate 5 toward the friction plate 2 and the mating plate 4, and the friction plate The brake is operated by causing a frictional engagement between 2 and the mating plate 4.

In the first embodiment shown in FIGS. 1-3, the surface of the pressure plate 5 facing the mating plate 4 is formed into the uneven surface 7 as shown in FIG. The concave-convex surface 7 has annular convex portions and annular concave portions concentric with the pressure plate 5 alternately, and two notch concave portions 7a 'are provided on each annular convex portion on one diameter line of the pressure plate 5. It is said that the recesses 7a are communicated with each other as a whole and are opened in the brake case 3 at both the outer peripheral end and the inner peripheral end of the pressure plate 5. Such an uneven surface 7 can be easily formed at the same time when the pressure plate 5 is cast.

FIG. 4 shows a second embodiment in which one surface of the mating plate 4 is formed as an uneven surface 7, and in this embodiment, a plurality of segments 8 made of an appropriate material such as a sintered material are circumferentially arranged. Are intermittently arranged and attached to the mating plate 4, and thus the segments 8 form the convex portions of the uneven surface 7, and the mating plate surface portion between the segments 8 is the concave portion 7a. The inner end of the segment 8 is positioned radially outward of the outer peripheral end position of the center hole of the partner plate 4, and the recess 7a of this embodiment is different from the recess 7a of FIG. There is a large opening in the brake case 3 at both the end side and the inner peripheral end side.

Regardless of whether the uneven surface 7 of FIG. 1 or FIG. 4 is adopted, the brake operation in which the friction plate 2 and the mating plate 4 as a whole are in pressure contact with the pressure receiving surface 14 and are frictionally engaged with each other. The braking release from the state can be easily obtained by rotating the brake arm 18 in the direction opposite to the arrow A in FIG. That is, at that time, the cam 17a is returned from the position shown by the chain line in FIG. 3 to the position shown by the solid line, and the force applied to the pressure plate 5 from the operating means side is eliminated, whereby the ball 6a of the cam means 6 is pressed. The pressing force exerted on the plate 5 is released. Since the friction plate 2 and the mating plate 4 push the pressure plate 5 in an attempt to restore from the elastically deformed state at the time of brake operation, the uneven surface 7 facilitates relative movement between the mating plate 4 and the pressure plate 5 as described above. As it awakens, the pressure plate 5 is pushed from the friction plate 2 and the mating plate 4 side to push the ball 6a on the slope of the cam groove 6b and rotate the ball 6a while moving the ball 6a from the shallow portion to the deep portion of the cam groove 6b. Then, the brake is released by sliding displacement to release the close contact with the facing mating plate 4. The recess 7a of the uneven surface 7 may be opened to the inside of the brake case 3 only on one side of the pressure plate 5 or the mating plate 4 on the outer peripheral end side or the inner peripheral end side.

In the above embodiment, the operating means for forcibly rotating the pressure plate 5 only in the brake actuating direction is provided, but this invention is of course disclosed in the above-mentioned Japanese Utility Model Laid-Open No. 57-150636. As described above, it can be implemented as a wet disc brake device provided with an operating means for forcibly rotating the pressure plate also in the braking release direction. In that case, the contact area reduced by the uneven surface 7 may be smaller than that shown in the figure. ..

[0015]

[Effect of the device]

 As is apparent from the above description, the present invention has been conventionally seen in a wet type disc brake of a type in which a mating plate is non-rotatably supported by an extremely simple structure in which one surface of the pressure plate or the mating plate is formed as a concave convex surface. It eliminates the difficulty of releasing the braking, and has high practical value.

[Brief description of drawings]

FIG. 1 is a perspective view of a pressure plate according to a first embodiment.

FIG. 2 is a vertical sectional side view of the first embodiment.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a perspective view of one mating plate in the second embodiment.

[Explanation of symbols]

 1 braked rotary shaft 1a spline 2 friction plate 3 brake case 3a case lid 4 mating plate 4a projection 5 pressure plate 5b actuation projection 6 cam means 6a ball 6b cam groove 7 uneven surface 7a recess 7a 'notch recess 8 segment 13 engagement Groove 17 Operation shaft 17a Cam

Claims (2)

[Scope of utility model registration request] 1. A brake shaft (1) slidably and non-rotatably supported by at least one friction plate (2) and a brake case (3) slidably and non-rotatably supported. At least two mating plates (4) are provided alternately, while a pressure plate (5) that is rotatably and slidably supported by the brake case (3) and is rotationally displaced by an operating means is provided at one end. The pressure plate (5) is provided between the pressure plate (5) and the brake case (3) so as to face the mating plate (4), and the pressure plate (5) faces the friction plate and the mating plate. In a wet disc brake device provided with a cam means (6) for pressing, one of the surfaces of the pressure plate (5) and the mating plate (4) at one end facing each other. It faces the wet disc brake device being characterized in that formed on the uneven surface to reduce the contact area between these surfaces by an appropriate amount (7). 2. The wet disk brake device according to claim 1, wherein a concave portion (7a) of the uneven surface (7) is provided such that the concave portion (7a) is always open in the brake case (3).