JP2015148277A - Disc brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a disc brake device capable of mounting a booster mechanism and capable of exerting a large pressing force with a small size, even in the disc brake device whose power is only hydraulic pressure.SOLUTION: A disc brake device 10 includes: an outer piston 18 which slides along an inner peripheral surface of a cylinder 14 by receiving a pressure of a working fluid supplied to the cylinder 14; an inner piston 16 which slides by receiving the pressure of the working fluid on the inner peripheral side of the outer piston 18; and a booster mechanism which uses one of the outer piston 18 and the inner piston 16 as an operating force supply source, and uses the other as a reaction force receiver, and which transmits a pressing force to a brake pad 28 when an operating force is supplied from the operating force supply source.

Description

  The present invention relates to a disc brake device, and more particularly to a disc brake device suitable for restricting the movement of a rotating body such as a spindle of a machine tool.

  In a machine tool such as a machining center, a disc brake device that restricts rotation of a main shaft is used for a purpose of maintaining a state where a rotor is stopped, unlike a brake device used in a vehicle.

  In such a machine tool, a cutting tool is applied to the workpiece while the rotation of the workpiece held by a chuck or the like provided on the main shaft is stopped, and processing such as cutting is performed. For this reason, if the main shaft rotates during processing, the processing accuracy of the workpiece is significantly reduced. Therefore, the disc brake device is required to have a capability of holding (pressing) the rotor with a strong force so that the main shaft does not rotate due to a force applied to the workpiece during cutting. Note that the force applied to the spindle increases as the machine tool increases in size.

  Usually, in a disc brake device using hydraulic pressure, in order to increase the pressing force, means are taken such as increasing the diameter of the piston, increasing the number of pistons, or increasing the number of calipers themselves. However, when such a means is adopted, the disc brake device itself is increased in size and the installation cost is increased. In addition, since various incidental facilities including a machining device exist around the main shaft of the machine tool, the arrangement space allowed for the disc brake device is narrow. For this reason, there is a situation in which the pressing force of the disc brake device cannot be increased by conventional means.

  Here, as a means for increasing the pressing force without changing the diameter or number of pistons, a booster mechanism as disclosed in Patent Document 1 or Patent Document 2 is known. The disc brake device disclosed in Patent Document 1 is a hydraulic disc brake device provided with a booster mechanism in order to provide a parking brake function. On the other hand, the disc brake device disclosed in Patent Document 2 is an electric disc brake device that converts rotational force generated by an electric motor into thrust in the rotor axial direction.

  In any of the disc brake devices, the booster mechanism uses an electric motor as an actuator, and a plurality of cylindrical screws combined in a telescopic type are provided inside the piston, and the booster mechanism is disposed between the screw and the piston. And the balance of the force applied to a booster mechanism is changed by operating the screw arrange | positioned inside and the screw arrange | positioned outside, and the amplification of force is aimed at.

Japanese Patent No. 5058189 Japanese Patent No. 5289182

  With the mechanisms disclosed in Patent Documents 1 and 2, the pressing force of the disc brake device can be increased without increasing the diameter of the piston or increasing the number thereof. However, the mechanisms for operating the booster mechanisms disclosed in Patent Documents 1 and 2 all convert rotational force into thrust in the axial direction of the rotor. It achieves screw co-operation and differential isolation. For this reason, the same structure cannot be applied to a disc brake device powered only by a hydraulic mechanism.

  An object of the present invention is to provide a disc brake device that can mount a booster mechanism and can exhibit a large pressing force even if it is a disc brake device that uses only hydraulic power.

  In order to achieve the above object, a disc brake device according to the present invention includes an outer piston that slides along an inner circumferential surface of the cylinder under the pressure of hydraulic oil supplied to the cylinder, and an inner circumferential side of the outer piston. The inner piston that slides under the pressure of the hydraulic oil and the outer piston or the inner piston are used as an operating force supply source, and the other piston is used as a reaction force receiver from the operating force supply source. And a booster mechanism that transmits a pressing force to the brake pad when power is supplied.

  Further, in the disc brake device having the above-described characteristics, the inner piston has a large diameter portion on the bottom side of the cylinder and a small diameter portion on the brake pad side, and the outer piston has an inner sliding surface. A constricted portion that slides the small-diameter portion of the inner piston, and the booster mechanism is accommodated in a pressing force input portion that is pressed by the constricted portion, an inner peripheral surface of the outer piston, and It is preferable that the elastic body includes a pressing force output unit having a diameter larger than that of the pressure input unit.

  When it has such a feature, the elastic body functions as a fluid in the sealed region. For this reason, according to Pascal's principle, a contact force larger than that of the pressing force input unit is generated on the surface in contact with the pressing force output unit, and functions as a booster mechanism.

  Further, it is desirable that the elastic body is constituted by the columnar pressing force input portion and a cylindrical pressing force output portion having a through hole through which the pressing force input portion is inserted.

  By having such a feature, it is possible to prevent the elastic member from being damaged due to bending or distortion generated between the pressing force input portion and the pressing force output portion.

  Further, in the disc brake device having the above characteristics, the booster mechanism is constituted by a cam lever, the contact point as the reaction force receiver is a fulcrum, the contact point as the operating force supply source is the force point, and the brake It is also possible to adopt a configuration in which the point of transmission of the pressing force to the pad is an action point and the length from the force point to the action point is made longer than the length from the fulcrum to the action point.

  By having such a feature, the cam lever functions as a booster mechanism using the principle of lever.

  According to the disc brake device having the above-described characteristics, a booster mechanism can be mounted even in a disc brake device that uses only hydraulic pressure as power. In addition, by mounting a booster mechanism, it is possible to exhibit a large pressing force with a small size.

It is a sectional side view showing the composition of the disc brake device concerning a 1st embodiment. 1 is a perspective view showing an external configuration of a disc brake device according to a first embodiment. It is an exploded perspective view of an internal mechanism mainly composed of a piston and a booster mechanism. It is a figure for demonstrating the effect | action of the force in the inner piston and booster mechanism of the disc brake apparatus which concerns on 1st Embodiment. It is a sectional side view which shows the non-operation state of the disc brake apparatus which concerns on 1st Embodiment. In the disc brake device concerning a 1st embodiment, both an inner piston and an outer piston are pushed into a rotor arrangement side field, and it is a sectional side view showing a state where a brake pad contacted a rotor. It is a sectional side view which shows a mode that an outer piston is pushed back with the pressing force of an inner piston, and a pressing force input part and a pressing force output part act as a booster mechanism. It is a figure which shows the structure of the disc brake apparatus which concerns on 2nd Embodiment. It is an exploded perspective view of an internal mechanism mainly composed of a piston and a booster mechanism. It is a figure for demonstrating the effect | action of the force in the inner piston and booster mechanism of the disc brake apparatus which concerns on 2nd Embodiment. It is a sectional side view which shows the non-operation state of the disc brake apparatus which concerns on 2nd Embodiment. In the disc brake device concerning a 1st embodiment, both an inner piston and an outer piston are pushed into a rotor arrangement side field, and it is a sectional side view showing a state where a brake pad contacted a rotor. It is a sectional side view which shows a mode that an inner piston is pushed back with the pressing force of an outer piston, and a cam lever acts as a booster mechanism.

Hereinafter, embodiments of the disc brake device according to the present invention will be described in detail with reference to the drawings.
First, the disc brake device according to the first embodiment will be described with reference to FIGS. FIG. 1 is a side sectional view showing a configuration of the disc brake device according to the embodiment, and FIG. 2 is a perspective view showing an appearance. FIG. 3 is an exploded perspective view of an internal mechanism mainly composed of a piston and a booster mechanism. Further, FIG. 4 is a diagram for explaining the action of force in the inner piston and the booster mechanism.

  The disc brake device 10 according to the embodiment is basically configured to include a cylinder 14, a piston 20, a booster mechanism 26, and a brake pad 28 in the caliper body 12. The disc brake device 10 shown in FIG. 1 and FIG. 2 is a so-called opposed type, but the characteristic configuration according to the present invention can be applied even to a floating type disc brake device. Is possible.

  The cylinder 14 is a recess formed in the facing surface of the rotor in the caliper body 12. Since the caliper body 12 according to the embodiment is an opposed type, a pair of cylinders 14 is formed so as to be line symmetric with respect to the rotor arrangement position. Each cylinder 14 is connected to a hydraulic path 30 so that hydraulic oil from a master cylinder and a pump (not shown) can be supplied.

  The piston 20 of the disc brake device 10 according to the present embodiment includes an outer piston 18 and an inner piston 16. The outer piston 18 is an element that slides with respect to the inner peripheral wall of the cylinder 14. The outer piston 18 according to the embodiment has a cylindrical shape, and an inner peripheral surface is provided with a throttle portion 18b that reduces the inner diameter. For this reason, the inner peripheral area of the outer piston 18 includes a bottom side area of the cylinder 14 (hereinafter simply referred to as the cylinder area 18a) and an arrangement side area of the brake pad 28 (hereinafter simply referred to as the pad area) via the throttle portion 18b. 18c). In the outer piston 18 according to the embodiment, a boss 18b1 protruding toward the cylinder region 18a is provided at the opening end of the throttle portion 18b. This is because the holding spring 32, which will be described in detail later, is positioned.

  The inner peripheral surface of the cylinder region 18a constitutes a sliding surface of the inner piston 16 described in detail later. On the other hand, a booster mechanism 26, which will be described in detail later, is disposed in the pad region 18c. Further, both the inner piston 16 and the booster mechanism 26 intervene in the opening of the throttle portion 18b.

  The inner piston 16 has a sliding part 16a and a pressing part 16b. The sliding portion 16 a is a portion that slides on the inner peripheral surface of the cylinder region 18 a of the outer piston 18. The pressing part 16 b is a part that intervenes in the opening of the throttle part 18 b in the outer piston 18 and plays a role of pressing the boost mechanism 26. The sliding portion 16a is formed at the tip of a flange-like flange portion that extends from the bottom surface side end portion of the cylinder 14 in the pressing portion 16b. A thin portion 16a1 is formed in the collar portion, and a solenoid-like holding spring 32 is disposed between the thin portion 16a1 and the outer edge of the boss 18b1 of the outer piston 18.

  In such an arrangement configuration, the outer piston 18 and the inner piston 16 behave as follows by the balance between the reaction force received by the outer piston 18 from the booster mechanism 26 and the elastic force of the holding spring 32. It will be.

  That is, when the reaction force is smaller than the elastic force, the outer piston 18 slides with the inner piston 16 toward the rotor arrangement side as the inner piston 16 is pressed. On the other hand, when the reaction force is larger than the elastic force, the outer piston 18 does not slide to the rotor arrangement side even when the inner piston 16 is pressed, and only the inner piston moves to the rotor arrangement side. Will be. At this time, the outer piston 18 slides toward the bottom surface side of the cylinder 14 due to the reaction force. A stop ring 34 is provided at the end of the cylinder region 18a of the outer piston 18 to prevent the inner piston 16 from falling off the cylinder region 18a.

  In the present embodiment, the booster mechanism 26 is constituted by an elastic member. The elastic member according to this embodiment includes a columnar pressing force input unit 22 and a cylindrical pressing force output unit 24, and the pressing force output unit 24 can be inserted through the pressing force input unit 22. It is configured. The elastic member may be an elastomer such as rubber or silicon, and may be one in which an incompressible fluid is sealed in a pressure-resistant soft container. Here, the pressing force input unit 22 may have a diameter that matches the opening diameter of the throttle unit 18b, and the pressing force output unit 24 includes an outer diameter that fits in the pad region 18c, and a pressing force input unit. It is preferable to have an inner diameter into which 22 can be inserted.

  A brake pad 28 is disposed on the rotor side of the booster mechanism 26 via a pressing plate 36. The pressing plate 36 is configured to be fitted into the pad region 18 c of the outer piston 18. With such a configuration, the region where the pressing force input unit 22 and the pressing force output unit 24 that constitute the boost mechanism 26 are arranged includes the pressing portion 16b of the inner piston 16, the throttle portion 18b of the outer piston 18, The pad region 18c and the pressing plate 36 are closed. For this reason, the pressing force input unit 22 and the pressing force output unit 24 formed of an elastic member each have the same action as the incompressible fluid, and generate an even contact force with respect to the surrounding wall surface. .

Next, the principle of the boost mechanism 26 in the disc brake device 10 according to the embodiment will be described. First, when pressure P (Pa) is applied to the end surface on the sliding portion 16a side having an area A1 (m ² ), the force acting on the inner piston 16 is P × A1 (N). Second, the area of one end face of the pressing force input portion 22 that receives pressure from the inner piston 16 is A2 (m ² ), and the portion that contacts the pressing plate 36 (the other end face of the pressing force input portion 22 and the pressing force output). The area of the end face of the part 24 is A3 (m ² ). Since the pressing force input unit 22 and the pressing force output unit 24 according to the embodiment perform the same operation as the liquid in the sealed container, when the area ratio of A2 and A3 is 1: 2, the pressing force input unit 22 and the pressing force output unit 24 act on the pressing plate 36. The force is 2 × P × A1 (N) due to Pascal's principle. Thus, the booster mechanism 26 according to the embodiment exhibits a boosting action according to the area ratio of A2 and A3.

  Next, the operation state of the disc brake device according to the embodiment will be described with reference to FIGS. FIG. 5 is a diagram illustrating a non-operating state, in which a gap is generated between the rotor and the brake pad 28.

  When hydraulic oil is supplied to the cylinder 14, the end surface on the sliding portion 16a side of the inner piston 16 is pressed, and the inner piston 16 tends to move in the rotor arrangement direction. At this time, the pressing force also acts on the bottom side end face of the cylinder 14 in the outer piston 18, but since the area of the pressure receiving surface is smaller than that of the inner piston 16, the acting pressing force is smaller than that of the inner piston 16. . On the other hand, a holding spring 32 is disposed between the outer piston 18 and the inner piston 16. For this reason, the outer piston 18 slides in the rotor arrangement direction together with the inner piston 16 by the action of the holding spring 32. By this operation, as shown in FIG. 6, the lining 28a of the brake pad 28 comes into contact with the sliding surface of the rotor.

  When the hydraulic oil pressing force is further increased, the pressing force input portion 22 and the pressing force output portion 24, which are elastic members, tend to be deformed by receiving a strong pressing force by the pressing portion 16b of the inner piston 16. The pressing force input unit 22 and the pressing force output unit 24 constituted by the elastic member perform the same action as the liquid in the closed region, and apply a uniform contact force to all the contact surfaces. Become. At this time, a contact force (reaction force against the force applied by the pressing portion 16b) from the rotor arrangement side to the bottom surface side of the cylinder 14 acts on the brake pad arrangement side surface of the throttle portion 18b of the outer piston 18. When the reaction force exceeds the elastic force of the holding spring 32, the outer piston 18 is pushed back to the bottom surface side of the cylinder 14, as shown in FIG. When the pushed-out outer piston 18 contacts the bottom surface of the cylinder 14, the internal pressure of the elastic members (pressing force input portion 22 and pressing force output portion 24) that have lost the force escape path is increased and applied by the inner piston 16. A force corresponding to the area ratio between the pressing portion 16b and the pressing plate 36 is generated with respect to the force.

  With this action, the disc brake device 10 can exhibit a high pressing force while using only the hydraulic mechanism as an operating source and reducing the appearance. When the hydraulic pressure is released, the brake pad 28 and the inner piston 16 are pushed back to predetermined positions by the action of the pad spring 38 and the holding spring 32.

  In the said embodiment, it described that the booster mechanism 26 was comprised by combining the pressing force input part 22 which is a cylindrical elastic member, and the pressing force output part 24 which is a cylindrical elastic member. This is because, when an elastic member is employed as the booster mechanism 26, the elastic member is deformed corresponding to the closed region that changes in accordance with the differential between the inner piston 16 and the outer piston 18. At this time, stress associated with bending or distortion is concentrated at a portion corresponding to the step portion formed between the inner piston 16 and the outer piston 18. For this reason, by dividing the elastic member at a portion corresponding to the step between the inner piston 16 and the outer piston 18, it is possible to suppress the occurrence of deterioration and breakage due to stress concentration.

  Therefore, when the main effect is to achieve the same effect as the above embodiment, the elastic member constituting the boost mechanism 26 is constituted by a single member having a form corresponding to the opening of the pad region 18c and the throttle portion 18b. You may do it. Of course, it may be configured by combining three or more elastic members. This is because even when the booster mechanism 26 has such a configuration, the effects of the disc brake device 10 according to the present embodiment can be achieved.

  Next, a second embodiment of the disc brake device according to the present invention will be described with reference to FIGS. Also in the disc brake device 10A according to the present embodiment, the piston 20 has a double structure including the inner piston 16 and the outer piston 18, and a booster mechanism 26A is provided between the brake pad 28 and the piston 20 (the inner piston 16 and the outer piston 18). The basic configuration including the above is the same as that of the disc brake device 10 according to the first embodiment. Therefore, elements having the same configuration are denoted by the same reference numerals in the drawings, and detailed description thereof is omitted.

  As a difference from the disc brake device 10 according to the first embodiment, first, a configuration of the booster mechanism 26A can be given, and a difference in structure of the piston 20 due to a difference in the configuration can be mentioned. .

  The booster mechanism 26A according to the present embodiment is configured by a rigid body. Specifically, the cam levers 40a and 40b each have a fulcrum O1, a force point O2, and an action point O3. In the case of the booster mechanism 26A according to the present embodiment, as shown in an exploded perspective view in FIG. 9, it is constituted by a pair of two cam levers 40a and 40b. The pair of cam levers 40a and 40b are configured such that portions (claws) having a contact portion corresponding to the fulcrum O1 are alternately engaged with each other. In addition, although the number of claws is not ask | required, it is desirable to set the width | variety so that it may become equal with the cam levers 40a and 40b which make a pair. By setting it as such a structure, the load balance with respect to the fulcrum O1 of the cam levers 40a and 40b which make a pair becomes favorable. Further, the cam levers 40a and 40b forming a pair do not shift in a direction perpendicular to the meshing direction.

  As shown in FIG. 10, the cam levers 40a and 40b have a contact portion with the inner piston 16 as a fulcrum O1, a contact portion with the outer piston 18 as a force point O2, and a contact portion with the pressure plate 28b in the brake pad 28. The action point is O3. The lever ratio of the cam levers 40a and 40b is determined by the ratio of the distance L1 from the fulcrum to the action point and the distance L2 from the force point to the action point (both are vertical distances in the figure).

  On the outer periphery of the cam levers 40a and 40b, there are provided holding clips 42 for holding the assembled state of the cam levers 40a and 40b and holding the posture for returning the inclination to the initial state.

  The outer piston 18 of the present embodiment also has a cylinder region 18a, a pad region 18c, and a throttle portion 18b. The difference from the outer piston 18 according to the first embodiment is that the throttle portion 18b has a surface on which the inner piston 16 slides. This is because by making the opening surface of the throttle portion 18b a sliding surface, a wide pressure receiving surface of the outer piston 18 can be secured, and a high pressing force can be obtained. A flange portion 16c of the inner piston 16, which will be described in detail later, is fitted into the cylinder region 18a. In the pad region 18c, a pair of cam levers 40a and 40b constituting the boost mechanism 26A is disposed.

The inner piston 16 includes a pressing portion 16b and a flange portion 16c. The pressing portion 16b is a portion that slides on the inner peripheral surface of the opening in the throttle portion 18b, and the fulcrum O1 of the cam levers 40a and 40b comes into contact with the distal end surface thereof. The flange portion 16c is a flange-shaped portion formed wider than the pressing portion 16b. By having the flange portion 16c, the inner piston 16 can be positioned with respect to the outer piston 18.
About another structure, it is the same as that of the disc brake apparatus 10 which concerns on 1st Embodiment mentioned above.

  Next, the operation state of the disc brake device 10A according to the present embodiment will be described with reference to FIGS. First, FIG. 11 is a diagram showing a state of the disc brake device 10A in an inoperative state. The flange 16c of the inner piston 16 is in contact with the bottom surface of the cylinder 14, and it can be read that there is a gap between the rotor and the brake pad 28.

  In this state, when hydraulic oil is supplied into the cylinder 14, a force that moves toward the rotor arrangement side is applied to the inner piston 16 and the outer piston 18 with respect to the pressure receiving surface. As a result, in the disc brake device 10A, the inner piston 16 and the outer piston 18, the booster mechanism 26A, the holding clip 42, and the brake pad 28 move in the rotor arrangement direction, and the lining 28a of the brake pad 28 is the rotor lining 28a. It contacts the sliding surface (see FIG. 12).

  When the lining 28a of the brake pad 28 abuts against the sliding surface of the rotor, the reaction force from the brake pad 28 increases, and the brake pad 28 cannot be moved to the rotor side. Here, the cam levers 40a and 40b constituting the boost mechanism 26A have the fulcrum O1, the force point O2, and the action point O3 (refer to FIG. 10 for each point), respectively, the inner piston 16, the brake pad 28, and the outer piston. 18 abuts. The cam levers 40a and 40b have a lever ratio of L1: L2. For this reason, the cam levers 40a and 40b receiving the pressing force of the outer piston 18 first rotate so as to push the force point O2 into the rotor arrangement side with the action point O3 as a base point. Thereby, the fulcrum O1 which is a contact point with the inner piston 16 moves to the bottom surface side of the cylinder 14, and the inner piston 16 is pushed back.

  When the flange 16c of the pushed inner piston 16 comes into contact with the bottom surface of the cylinder 14, the reaction force of the inner piston 16 is improved and the fulcrum O1 of the cam levers 40a and 40b is fixed. Thereby, the pressing force from the outer piston 18 acts as a load on the action point O3.

  With such an operation, the cam levers 40a and 40b function as the booster mechanism 26A. In the drawings shown in FIGS. 11 to 13, the movements of the inner piston 16, the outer piston 18, and the cam levers 40a and 40b are shown larger than the actual movements so that the movements can be easily understood. For this reason, the cam levers 40a and 40b are shown so that the position of the action point O3 is greatly shifted as the cam levers 40a and 40b are rotated, but actually, the action point O3 is not shifted as the lever ratio is reversed.

10, 10A ......... Disc brake device, 12 ... ... Caliper body, 14 ... ... Cylinder, 16 ... ... Inner piston, 16a ... ... Sliding part, 16a1 ... ... Thin part, 16b ... ... Pressing Part, 16c ......... collar part, 18 ... ... outer piston, 18a ... ... cylinder area, 18b ... ... throttle part, 18b1 ... ... boss, 18c ... ... pad area, 20 ... ... piston, 22 ......... Pressure force input section, 24 ......... Pressure force output section, 26, 26A ......... Boost mechanism, 28 ......... Brake pad, 28a ......... Lined, 28b ......... Pressure plate, 30 ... ... Hydraulic path, 32 ......... Retaining spring, 34 ......... Retaining ring, 36 ......... Pressing plate, 38 ......... Pad spring, 40a, 40b ......... Cam lever, 42 ......... Holding clip.

Claims (4)

An outer piston that slides along the inner circumferential surface of the cylinder under the pressure of hydraulic oil supplied to the cylinder;
An inner piston that slides under the pressure of the hydraulic oil on the inner peripheral side of the outer piston;
One of the outer piston and the inner piston is used as an operating force supply source, and the other piston is used as a reaction force receiver, and the pressing force is transmitted to the brake pad when the operating force is supplied from the operating force supply source. Force mechanism,
A disc brake device comprising: The inner piston has a large diameter part on the bottom side of the cylinder and a small diameter part on the brake pad side,
The outer piston includes a constricted portion that slides the small-diameter portion of the inner piston on the inner peripheral sliding surface,
The booster mechanism includes a pressing force input portion that is pressed by the constricted portion, and an elastic body that includes a pressing force output portion that is accommodated in an inner peripheral surface of the outer piston and has a larger diameter than the pressing force input portion. The disc brake device according to claim 1, wherein   The said elastic body is comprised from the cylindrical pressing force input part and the cylindrical pressing force output part provided with the through-hole which penetrates the said pressing force input part. Disc brake device. The boost mechanism is constituted by a cam lever,
The contact point as the reaction force receiver is a fulcrum, the contact point as the operating force supply source is the force point, and the pressure transmission point to the brake pad is the action point.
2. The disc brake device according to claim 1, wherein a length from the force point to the action point is made longer than a length from the fulcrum to the action point.

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