JP6570466B2 - Brake device for vehicle - Google Patents

Description

  The present invention relates to a vehicle brake device.

  A vehicle provided for industrial use such as a forklift is provided with a brake device on a power transmission shaft from a power source such as an engine to wheels. This brake device has one or more brake discs on the power transmission shaft side and one or more brake plates on the housing side. For example, when there are a plurality of both, each brake disk and each brake plate are alternately arranged, and the brake plate is pressed against the brake disk by a hydraulic piston driven in the direction of the axis of the power transmission shaft. The required braking is performed. The hydraulic piston loses its pressing force when the supply of hydraulic oil is stopped, thereby releasing the braking operation. When the pressing force disappears, the hydraulic piston returns to the original position by the action of a restoring spring or the like.

  When the hydraulic piston returns to the original position, a gap is formed between the piston existing at the original position and the brake plate. For this reason, whenever it act | operates, after moving from an original position and closing a clearance gap, a hydraulic piston contacts a brake plate for the first time, and starts substantial braking operation | movement.

  In such a brake device, when the brake disc or the brake plate is worn due to use over time, the gap described above is increased accordingly, and the stroke of the hydraulic piston is correspondingly increased. Cause.

  For this reason, conventionally, it has been proposed to correct the piston stroke to be small by adjusting the return amount of the hydraulic piston by manual screw adjustment at the time of inspection or the like.

  Alternatively, in Patent Document 1, a plurality of small pistons are arranged along the circumferential direction of the brake disc and the brake plate, a rod that moves integrally with the small pistons is provided, and a retaining ring is loosely fitted onto the rod. The size of the gap provided between the wheel and the housing is the stroke of the small piston, and the position of the retaining ring relative to the rod can be changed by sliding the retaining ring against the rod. It describes what can automatically adjust the piston stroke during wear.

  In Patent Document 2, a plurality of small pistons are arranged along the circumferential direction of the brake disc and the brake plate, and the sleeve is loosely fitted to the pistons, and the size of the gap provided between the sleeve and the housing is reduced. It describes the piston stroke that can be adjusted automatically by allowing the piston to slide relative to the sleeve so that the position of the sleeve relative to the piston can be changed. Yes.

Japanese Patent No. 5211270 JP 2009-150486 A

  Conventional manual screw adjustment requires periodic adjustments such as during an annual inspection of the vehicle. In addition, the automatic adjustment requires a large number of components in order to achieve the above-described function, and the structure of the apparatus is complicated.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to enable automatic adjustment of a piston stroke in response to wear of a brake disc and a brake plate with a minimum number of components in a vehicle brake device.

In order to achieve this object, the vehicle brake device of the present invention includes:
A housing that houses the brake disc and brake plate together with the power transmission shaft;
A piston that slides against the housing while receiving the first sliding resistance from the housing when the hydraulic oil is supplied, and generates a braking force to the power transmission shaft by pressing the brake disc and the brake plate. When,
A stopper capable of sliding in the same direction as the piston with respect to the housing while receiving a second sliding resistance greater than the first sliding resistance from the housing;
A first end surface formed opposite to each other at a distance in the moving direction of the piston in the piston, and a second end surface closer to the brake disc and the brake plate than the first end surface;
A third end surface formed at a distance in the direction of movement of the piston at the stopper, and a fourth end surface closer to the brake disc and the brake plate than the third end surface;
It is arrange | positioned between a piston and a stopper, the 2nd end surface of a piston and the 4th end surface of a stopper contact, and a 1st end surface and 3rd at the time of a contact with a 2nd end surface and a 4th end surface An elastic body that exerts a force larger than the first sliding resistance and smaller than the second sliding resistance on the piston and the stopper so that a gap in the moving direction of the piston is formed between the end surface of the piston and the stopper. It is characterized by having.

  According to such a configuration, the piston can move relative to the stopper within the above-described gap, and the size of the gap corresponds to the piston stroke. The piston generates a braking force by being moved toward the brake disk and the brake plate by the hydraulic oil. When braking is not performed, the original position is restored by the action of the elastic body.

  When wear occurs on the brake disc and the brake plate, the piston does not reach the brake disc and the brake plate only by moving the piston stroke corresponding to the gap. In that case, both the piston and the stopper are moved in a direction approaching the brake disc and the brake plate by the force of the hydraulic oil, and a braking force is generated. The movement amount at this time corresponds to the wear amount, and the stopper is displaced by a distance corresponding to the wear amount by this movement. Accordingly, the piston stroke is automatically adjusted so that the piston stroke does not increase even when the brake disc and the brake plate are worn.

  According to the vehicle brake device of the present invention, both the brake disc and the brake plate are configured by the annular plate body, and both the piston and the stopper are along the circumferential direction of the annular brake disc and the brake plate. It is preferable that the annular body is arranged.

  According to the vehicle brake device of the present invention, it is preferable that the second sliding resistance between the housing and the stopper is expressed by an O-ring provided between the housing and the stopper.

  According to the vehicle brake device of the present invention, it is preferable that the first sliding resistance between the housing and the piston is expressed by a sealing material that seals between the housing and the piston.

  According to the vehicle brake device of the present invention, it is preferable that one of the piston and the stopper is disposed on the inner peripheral side and the other is disposed on the outer peripheral side.

  According to the present invention, when a brake disk or a brake plate is worn by a simple configuration in which a stopper is provided in addition to a piston in a normal vehicle brake device, that is, by a minimum number of parts, The piston stroke can be adjusted automatically.

It is sectional drawing of the brake device for vehicles of embodiment of this invention. It is a figure which expands and shows the principal part in FIG. It is a figure which shows the state which the piston moved toward the brake disc and the brake plate from the state shown in FIG. It is a figure which shows the state which the piston and the stopper further moved toward the brake disc and the brake plate from the state shown in FIG. It is a figure which shows the state which the piston returned to the new original position from the state shown in FIG.

  In FIG. 1, reference numeral 10 denotes a housing, and a first housing member 11, a second housing member 12, a third housing member 13, and a fourth housing member 14 are fastened to each other by bolts 15 and 16. As a result, a box-like structure is constructed. A power transmission shaft 17 for a vehicle is supported inside the housing. In FIG. 1, the power transmission shaft 17 is indicated by a one-dot chain line for simplicity. The power transmission shaft 17 transmits a rotational force from a power source such as an engine in the vehicle to the wheels.

  A disk hub 18 is attached to the power transmission shaft 17 so as to be integrally rotatable. A first concavo-convex portion 19 is formed on the outer periphery of the disc hub 18, and by being fitted into the concavo-convex portion 19, the disc hub 18 can rotate integrally with the disc hub 18 and move in the axial direction of the power transmission shaft 17. In the illustrated example, a plurality of brake disks 20 are provided. The brake disk 20 is configured by a plate-like circular annular body whose inner periphery can be fitted into the first uneven portion 19, and is arranged concentrically with the axis of the power transmission shaft 17.

  A second uneven portion 21 is formed on the inner periphery of the second housing member 12 in the housing 10. In the illustrated example, a plurality of brake plates 22 are configured so as to be non-rotatable and movable in the axial direction of the power transmission shaft 17 by being fitted into the second uneven portion 21. The brake plate 22 is configured by a plate-like circular annular body whose outer periphery is configured to fit into the second uneven portion 21, and is arranged concentrically with the axis of the power transmission shaft 17.

  The plurality of brake disks 20 and the plurality of brake plates 22 in the illustrated example are alternately arranged so as to overlap each other. These can be singular. The brake disk 20 has an outer diameter smaller than the inner diameter of the second uneven portion 21, and is thus configured to freely rotate without being caught in the second uneven portion 21. The brake plate 22 has an inner diameter larger than the outer diameter of the first concavo-convex portion 19, and is thus configured to be able to maintain a non-rotatable state without being caught in the first concavo-convex portion 19.

  The brake disc 20 and the brake plate 22 are both housed in an oil chamber 23 in the housing, and thus constitute a wet multi-plate brake.

  Hereinafter, a detailed description will be given with reference to FIGS. 1 and 2. In order to easily understand the drawing, some symbols are described only in FIG. 2 and are not described in FIG. 1, thereby preventing FIG. 1 from becoming extremely complicated.

  In the inner periphery of the second housing member 12, it is concentric with the power transmission shaft 17 at a position spaced from the position where the brake disk 20 and the brake plate 22 are disposed in the housing 10 in the axial direction of the power transmission shaft 17. An annular first sliding surface 25 is formed. The fourth housing member 14 in the housing 10 is formed with a second sliding surface 26 that is concentric and annular with the power transmission shaft 17 at a position on the inner peripheral side with respect to the first sliding surface 25. Yes. Further, a third sliding surface having a smaller diameter than the second sliding surface 26 is provided on the outer periphery of the fourth housing member 14 at a position closer to the brake disc 20 and the brake plate 22 than to the second sliding surface 26. 27 is formed. The third sliding surface 27 is also concentric with the power transmission shaft 17 and is formed in an annular shape. As a result, the first sliding surface 25 that is the inner peripheral surface and the second sliding surface 26 that is the outer peripheral surface. The third sliding surface 27 that is the outer peripheral surface is formed concentrically with respect to the axis of the power transmission shaft 17. An annular end surface 28 formed toward the brake disc 20 and the brake plate 22 is provided at a boundary portion between the second sliding surface 26 and the third sliding surface 27.

  An annular piston 30 is disposed between the first sliding surface 25 and the second sliding surface 26. The piston 30 has an outer peripheral surface 31 that slidably contacts the first sliding surface 25 and an inner peripheral surface 32 that slidably contacts the second sliding surface 26, whereby the piston 30 The brake disc 20 and the brake plate 22 are arranged with the central axis in common.

  A hydraulic oil supply chamber 33 is formed between the second housing member 12 and the fourth housing member 14 at the rear portion of the piston 30 with the side close to the brake disc 20 and the brake plate 22 in the piston 30 as the front side. Yes. When the pressurized hydraulic fluid is supplied to the supply chamber 33, the piston 30 moves toward the brake disc 20 and the brake plate 22 in the axial direction of the power transmission shaft 17. A pressing end surface 34 is formed at the front end of the piston 30, and the pressing end surface 34 can press the brake disc 20 and the brake plate 22 that are arranged to overlap each other. The first housing member 11 is formed with a pressure receiving surface 35 for receiving a pressing force transmitted from the piston 30 via the brake disc 20 and the brake plate 22.

  A snap ring 36 having a rectangular cross section is fitted in an annular groove 29 formed on the inner periphery of the piston 30. By this fitting, the snap ring 36 can be handled as an element constituting a part of the piston 30. That is, the whole combining the piston 30 and the snap ring 36 can be handled as one piston.

  The snap ring 36 can contact the end face 28 of the fourth housing member 14. Thus, the piston 30 can reciprocate between a position where the snap ring 36 contacts the end face 28 of the fourth housing member 14 and a position where the pressing end face 34 presses the brake disc 20 and the brake plate 22. An annular inner peripheral projection 37 having a rectangular cross section is formed integrally with the front end of the piston 30. A first end surface 38 is configured by the front end surface of the piston 30 in the snap ring 36, and a second end surface 39 is configured by the rear end surface of the piston 30 in the inner peripheral projection 37.

  An annular first sealing material 41 that seals between the piston 30 and the first sliding surface 25 is accommodated in the annular groove 40 formed in the outer peripheral surface of the piston 30. The annular groove 42 formed along the circumferential direction of the second sliding surface 26 accommodates an annular second sealing material 43 that seals between the piston 30 and the second sliding surface 26. Yes. The first and second sealing materials 41 and 43 prevent high-pressure hydraulic oil supplied to the supply chamber 33 from flowing into the oil chamber 23.

  A stopper 45 is disposed concentrically with the piston 30 at a position on the inner peripheral side of the piston 30. The stopper 45 is formed of an annular body having a convex cross section, and has an inner peripheral surface 46 slidably in contact with the third sliding surface 27 and an inner surface of the first end surface 38 of the snap ring 36. It has the 3rd end surface 47 which can be in contact with a peripheral part, and the 4th end surface 48 which can be in contact with the 2nd end surface 39 of piston 30. FIG. That is, the third end surface 47 is formed toward the rear side of the piston 30, and the fourth end surface 48 is formed toward the front side of the piston 30.

  The distance from the first end face 38 to the second end face 39 is set to be larger than the distance from the third end face 47 to the fourth end face 48. That is, as shown in FIGS. 1 and 2, when the fourth end surface 48 is in contact with the second end surface 39, a gap B is formed between the first end surface 38 and the third end surface 47. It is configured. The gap B is set to be equal to a disc gap described later, that is, a set distance from the piston 30 waiting in the original position to the brake disc 20 and the brake plate 22.

  Another end surface 49 is formed at a location radially outside the third end surface 47 of the stopper 45. The end surface 49 is formed at a position farther from the first end surface 38 than the third end surface 47. Between the first end surface 38 of the snap ring 36 and the end surface 49 of the stopper 45, a return spring 50 as an elastic body, which is formed of an annular wave spring, is disposed. The return spring 50 acts to press the first end surface 38 and the end surface 49 in a direction in which the first end surface 38 and the end surface 49 are separated from each other. In other words, the return spring 50 has a snap ring 36, that is, the piston 30, in a direction in which the space between the first end surface 38 and the third end surface 47 opens and the second end surface 39 and the fourth end surface 48 approach each other. And act to press the stopper 45.

  The third sliding surface 27 is formed with an annular groove 52 in the outer peripheral direction. An O-ring 53 is fitted in the annular groove 52.

  As described above, the stopper 45 is movable in the axial direction of the power transmission shaft 17 while sliding along the third sliding surface 27 while compressing the O-ring 53.

  The piston 30 slides along the first sliding surface 25 and the second sliding surface 26, and at that time, receives a first sliding resistance from the housing 10. The first sliding resistance is caused by the frictional force between the piston 30 and the first and second sliding surfaces 25 and 26, and the first and second sealing members 41 and 43 have a sealing function. It is also caused by the repulsive force caused by being compressed in order to exert the effect.

  The stopper 45 slides along the third sliding surface 27, and at that time, receives the second sliding resistance from the housing 10. This second sliding resistance is caused by the frictional force between the stopper 45 and the third sliding surface 27 and also caused by the repulsive force caused by the stopper 45 compressing the O-ring 53.

  By adjusting the frictional force and the repulsive force described above, the second sliding resistance from the housing 10 to the stopper 45 is larger than the first sliding resistance from the housing 10 to the piston 30. It is configured. The force exerted on the piston 30 and the stopper 45 by the return spring 50 is adjusted so as to be larger than the first sliding resistance and smaller than the second sliding resistance.

  An operation for adjusting the gap will be described. 1 and 2 show a state before adjustment. That is, the pressurized hydraulic fluid is not supplied to the supply chamber 33, and therefore, the piston 30 exists at the original position away from the brake disc 20 and the brake plate 22. At this time, when normal, the distance from the brake disc 20 and the brake plate 22 to the piston, that is, the size of the gap A called the disc gap should be equal to the set distance, that is, the size of the gap B. is there. However, when the brake disc 20 and the brake plate 22 are worn over time, the gap A becomes larger than the gap B as shown. The gap A may be larger than the gap B in this way even immediately after the assembly of the brake device. If this is not adjusted, the stroke of the piston 30 will be excessive, and the brake pedal stroke of the vehicle will be excessive accordingly.

  When pressurized hydraulic fluid is supplied to the supply chamber 33 for brake operation from the state shown in FIGS. 1 and 2, the piston 30 moves toward the brake disk 20 and the brake plate 22, thereby the shaft of the power transmission shaft 17. It is moved in the direction of the heart.

  Then, as described above, since the force exerted on the piston 30 and the stopper 45 by the return spring 50 is smaller than the second sliding resistance that the stopper 45 receives from the third sliding surface 27 and the O-ring 53, the return spring The piston 30 moves while compressing 50, and the stopper 45 does not move. As a result, the gap B is closed, and the inner peripheral edge of the first end surface 38 of the snap ring 36 of the piston 30 contacts the third end surface 47 of the stopper as shown in FIG.

  At this time, since the gap A shown in FIG. 2 is larger than the gap B as described above, even when the gap B between the snap ring 36 and the stopper 45 of the piston 30 disappears, the piston 30 and the brake disc A gap C still remains between 20 and the brake plate 22.

  Thereafter, since the pressure applied by the hydraulic oil is greater than the second sliding resistance, the piston 30 and the stopper 45 whose third end surface 47 is in contact with the first end surface 38 move integrally. .

  Then, as shown in FIG. 4, the pressing end surface 34 of the piston 30 comes into contact with the brake disk 20 and the brake plate 22, and a required braking force is applied to the brake disk 20 and the brake plate 22 from the piston 30 by the action of the hydraulic oil. At that time, the piston 30 and the stopper 45 stop moving.

  From this state, when the pressure applied by the hydraulic oil is released and the braking force is released, the first sliding resistance received by the piston 30 from the housing 10 side and the force from the return spring 50 are applied to the stopper 45 by the housing 10. Since the first sliding resistance received by the piston 30 from the housing 10 side is smaller than the force from the return spring 50, the following operation is performed. That is, the stopper 45 does not move with respect to the third sliding surface 27, and the piston 30 moves along the first and second sliding surfaces 25, 26 by the force of the return spring 50. It moves in a direction away from the brake plate 22.

  As a result of this movement, as shown in FIG. 5, the second end face 39 of the piston 30 contacts the fourth end face 48 of the stopper 45, thereby preventing further movement of the piston 30. At this time, a gap B is formed between the third end surface 47 of the stopper 45 and the first end surface 38 of the piston 30 in the same manner as described above. That is, the piston 30 is stopped in a state in which the pressing end surface 34 is at a distance equal to the gap B from the brake disc 20 and the brake plate 22. Accordingly, the size of the disc gap at this time is equal to the size of the set value, that is, the size of the gap B.

  The next brake operation is started with the position of the piston 30 shown in FIG. 5 as the original position. That is, the disc gap can be adjusted to a size equal to the gap B that is the set value.

  When the brake disc 20 and the brake plate 22 are further worn over time, the adjustment can be automatically performed in the same manner. Also, the large gap A shown in FIG. 2 may be formed at the time of manufacturing the brake device, at the time of inspection, or when reassembling after repair. In this case, the disk gap can be adjusted in the same manner. it can.

  In other words, according to the present invention, the stopper 45 serving as a reference when the disc gap is set to a predetermined set value is movable, and when the brake disc 20 and the brake plate 22 are worn or when the device is assembled, By making the position of the stopper 45 changeable, the disc gap, that is, the stroke of the piston 30 is automatically adjusted so as to always become a predetermined set value regardless of the wear of the brake disc 20 and the brake plate 22. Can do.

  Therefore, according to the present invention, the vehicle has a simple configuration having only one annular piston 30 similar to the brake disc 20 and the brake plate 22 and one annular stopper 45 concentric with the piston 30. The disc gap of the brake device, that is, the stroke of the piston 30 can be automatically adjusted.

  In the above description, the piston 30 is disposed on the outer peripheral side and the stopper 45 is disposed on the inner peripheral side. However, according to the present invention, the stopper 45 is disposed on the outer peripheral side and the piston 30 is disposed on the inner peripheral side. It is also possible to adopt a configuration arranged on the side. The form of the elastic body is also arbitrary.

  In the above, the O-ring 53 is exemplified as a means for giving the stopper 45 sliding resistance. Since the O-ring 53 is supplied in various and large quantities as a commercial product, the required sliding resistance can be easily imparted to the stopper 45 without using a special structure. However, in the present invention, it is of course possible to impart sliding resistance to the stopper 45 by means other than the O-ring 45.

  Further, the first end surface 38 and the second end surface 39 of the piston 30 face each other, and the third end surface 47 and the fourth end surface 48 of the stopper 45 enter between them. It is also possible to adopt a configuration in which the end faces face each other and a pair of end faces of the piston 30 enter between the end faces.

  In the drawing, an example in which an inner peripheral projection 37 is provided on the front side of the piston 30 and a snap ring 38 is arranged on the rear side thereof is illustrated. However, instead of this, it is also possible to provide an inner peripheral projection on the rear side of the piston 30 and to arrange a snap ring on the front side of the piston 30.

  In the above description, the example in which the brake disc 20 is a rotary type and the brake plate 22 is a non-rotational type has been described. However, instead of this, the brake disk 20 may be of a non-rotating type and the brake plate 22 may be of a rotating type.

  In addition, for example, various modifications can be configured within the scope of the present invention by setting and changing the resistance of each part and the elastic force of the elastic body.

DESCRIPTION OF SYMBOLS 10 Housing 17 Power transmission shaft 20 Brake disk 22 Brake plate 25 1st sliding surface 26 2nd sliding surface 27 3rd sliding surface 30 Piston 33 Hydraulic oil supply chamber 38 1st end surface 39 2nd end surface 41 1st sealing material 43 2nd sealing material 45 Stopper 47 3rd end surface 48 4th end surface 50 Return spring (elastic body)
53 O-ring

Claims (5)

A housing that houses the brake disc and brake plate together with the power transmission shaft;
A piston that slides against the housing while receiving the first sliding resistance from the housing when the hydraulic oil is supplied, and generates a braking force to the power transmission shaft by pressing the brake disc and the brake plate. When,
A stopper capable of sliding in the same direction as the piston with respect to the housing while receiving a second sliding resistance greater than the first sliding resistance from the housing;
A first end surface formed opposite to each other at a distance in the moving direction of the piston in the piston, and a second end surface closer to the brake disc and the brake plate than the first end surface;
A third end surface formed at a distance in the direction of movement of the piston at the stopper, and a fourth end surface closer to the brake disc and the brake plate than the third end surface;
It is arrange | positioned between a piston and a stopper, the 2nd end surface of a piston and the 4th end surface of a stopper contact, and a 1st end surface and 3rd at the time of a contact with a 2nd end surface and a 4th end surface An elastic body that exerts a force larger than the first sliding resistance and smaller than the second sliding resistance on the piston and the stopper so that a gap in the moving direction of the piston is formed between the end surface of the piston and the stopper. And a brake device for a vehicle. Both the brake disc and brake plate are composed of annular plates,
2. The vehicle brake device according to claim 1, wherein each of the piston and the stopper is an annular body arranged along a circumferential direction of the annular brake disk and the brake plate.   3. The vehicle brake device according to claim 2, wherein the second sliding resistance between the housing and the stopper is expressed by an O-ring provided between the housing and the stopper.   The vehicle according to any one of claims 1 to 3, wherein the first sliding resistance between the housing and the piston is expressed by a sealing material that seals between the housing and the piston. Brake device.   The vehicular brake device according to any one of claims 1 to 4, wherein one of the piston and the stopper is disposed on the inner peripheral side, and the other is disposed on the outer peripheral side thereof.

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