JP5196490B2 - Negative-acting brake device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the brake force of a vacuum operated brake device without increasing the size of the device. <P>SOLUTION: The vacuum operated brake device 1 includes a brake lining 4 which attached to the tip of a brake lever 2 installed turnably round a revolving shaft 3 and is pressed by a tensile coil spring 5 to the peripheral surface 10a of a rotary shaft 10 for applying a braking force to inhibit the rotary shaft 10 from turning. When an actuator 6 is actuated, the brake lever 2 turns to make a change to a brake released condition. When the angle formed by a line segment B passing the revolving shaft 3 and the abutting position 4A of the brake lining 4 to the rotary shaft peripheral surface 10a and the normal C to the peripheral surface 10a of hte rotary shaft 10 drawn to the abutting position 4A is represented by &alpha; and the friction angle between the peripheral surface 10a and the brake lining 4 is represented by &beta;, the relation &alpha;&lt;&beta; is satisfied. When the rotary shaft 10 rotates in the direction of Arrow A in the brake applied condition, a large braking force is applied to the rotary shaft 10 by the self boosting action. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  In the present invention, the brake lining is pressed against the rotating shaft to be braked by an elastic member such as a spring member so that the rotating shaft is not braked so that the rotating shaft is not rotated. The present invention relates to a negatively operated brake device configured to separate a brake lining from a rotating shaft against the force).

  For example, as shown in FIG. 2, this type of brake device includes a pair of brake levers 102 and 103 arranged symmetrically on both sides of a rotation shaft 100 such as a motor, and the rotation shafts of these brake levers 102 and 103. Brake linings 104 and 105 are affixed to the inner part facing the outer peripheral surface 100a of 100. The rear end portions 102a and 103a of the brake levers 102 and 103 are rotatably supported by rotating support shafts 106 and 107, respectively. The brake levers 102 and 103 can rotate in directions toward and away from the outer peripheral surface 100a of the rotation shaft 100 around the rotation support shafts 106 and 107. An actuator 108 is bridged between the rear ends of the brake pads 102 and 103 and the rear ends of the brake pads 102 and 103 are driven. The actuator 108 is driven to move the tip portions 102b and 103b of the brake levers 102 and 103 to the left and right. It can be opened and closed.

  A spring member 109 for generating a braking force is stretched between the front end portions 102b and 103b of the brake levers 102 and 103. Usually, the brake levers 102 and 103 are pulled in a direction in which they approach each other by the spring member 109. It has been. As a result, the left and right brake linings 104 and 105 are pressed against the outer peripheral surface 100a of the rotating shaft 100, and a holding torque (braking force) for holding the rotating shaft 100 in that position is applied. Therefore, the braking force acting on the rotating shaft 100 is defined by the spring force of the spring member 109. When the actuator 108 is driven, the left and right brake levers 102 and 103 are spread left and right against the spring force, the brake linings 104 and 105 are separated from the outer peripheral surface 100a of the rotating shaft 100, and the holding torque is released. Can rotate freely.

  In the motor-driven drum brake disclosed in Patent Document 1, the left and right brake shoes are held at the brake release position separated from the rotation shaft by the spring force. When the electric actuator is driven, the brake shoe is pushed left and right to form a braking state in which a braking force is applied to the rotating shaft, and the braking force is defined by the electric actuator.

JP 2001-221268 A

  Since the braking device shown in FIG. 2 is applied with a braking force by a spring force, it is more compact, simpler and less expensive than a configuration in which the braking force is generated by an actuator as disclosed in Patent Document 1. There is an advantage. However, in order to obtain a large braking force, it is necessary to increase the spring force of the spring member for generating the braking force, and accordingly, it is necessary to increase the size of the actuator for releasing the braking force. Will be damaged.

  In view of this point, an object of the present invention is to increase the braking force acting on the rotary shaft without increasing the generated spring force of the spring member for generating the braking force. The object is to propose a negatively actuated brake device that can avoid an increase in size.

  In order to solve the above problems, the negatively operated brake device of the present invention is characterized in that it is configured as follows. Note that the reference numerals in parentheses are given for ease of understanding, and are not intended to limit the present invention to the embodiments described later.

That is, the negatively operated brake device (1) of the present invention is
A brake lever (2) rotatable about a predetermined pivot (3);
A brake lining (4) attached to the brake lever (2);
The brake lever (2) is rotated about the rotation support shaft (3), and the brake lining (4) is pressed against the outer peripheral surface (10a) of the rotation shaft (10) to be braked. A holding elastic member (5) held at the braking position (2A),
The brake lever (2) is rotated in the reverse direction about the rotation support shaft (3), so that the brake lining (4) is separated from the outer peripheral surface (10a) of the rotation shaft (10). An actuator (6) to be moved to the brake release position (2B)
The brake lining (4) is a flat plate having a constant thickness,
The contact position of the center the relative (3A) and said outer peripheral surface (10a) brake lining (4) of the rotation shaft (3) (4A) and a line segment passing through (B) are abutting position (4A ) With respect to the normal line (C) of the outer peripheral surface (10a) drawn to the rotation axis (10),
If the angle formed by the line segment (B) and the normal line (C) is α and the friction angle of the brake lining (4) with respect to the outer peripheral surface (10a) of the rotating shaft (10) is β, α <β It is characterized by satisfying the relationship.

  In the braking state in which the brake lining of the brake lever is pressed against the outer peripheral surface of the rotating shaft by the holding elastic member, the angle α is smaller than the friction angle β, so that the so-called self-boosting action works and the holding elastic member A braking force larger than the frictional force generated between the brake lining and the outer peripheral surface of the rotating shaft is applied to the rotating shaft by the pressing force of.

  In the negative operation type brake device of the present invention, the brake lever that presses the brake lining against the outer peripheral surface of the rotating shaft is appropriately set so that the biasing force generated by the elastic member generates the force between the brake lining and the outer peripheral surface of the rotating shaft. A braking force larger than the friction force is applied to the rotating shaft. Therefore, an increase in the size of the elastic member for increasing the braking force and an increase in the size of the actuator associated therewith can be avoided.

It is explanatory drawing which shows the negative action type brake device to which this invention is applied. It is explanatory drawing which shows a general negative action type brake device.

  Hereinafter, an embodiment of a negative operation type brake device to which the present invention is applied will be described with reference to FIG.

  The negatively operated brake device 1 according to the present embodiment includes a brake lever 2 disposed at a side position of a rotary shaft 10 such as a motor shaft to be braked. The brake lever 2 includes a linear tip portion 2a facing the outer peripheral surface 10a of the rotary shaft 10, and an arm portion that is bent in a direction away from the rotary shaft 10 from the rear end of the tip portion 2a and extends linearly. 2b and a rear end portion 2c that is slightly bent from the rear end of the arm portion 2b and extends linearly. At the boundary position between the arm portion 2b and the rear end portion 2c, the brake lever 2 is rotatably supported by the rotation support shaft 3, and rotates on an orthogonal plane orthogonal to the rotation center line 10b of the rotation shaft 10. Is possible.

  A brake lining 4 (brake pad, friction plate) having a certain thickness is attached to a side surface of the distal end portion 2a of the brake lever 2 facing the outer peripheral surface 10a of the rotating shaft 10. One end of a tension coil spring 5 is connected to the rear end portion 2 c of the brake lever 2, and the brake lever 2 is attached to the front end portion 2 a by the spring force of the tension coil spring 5. 4a is held at the braking position 2A in a state of being pressed against the outer peripheral surface 10a of the rotary shaft 10.

  An actuator 6 is connected to the rear end portion 2 c of the brake lever 2. When the actuator 6 is driven, the brake lever 2 is rotated about the rotation support shaft 3 by the actuator 6, and the brake lining 4 attached to the tip end portion 2 a is separated from the outer peripheral surface 10 a of the rotation shaft 10. It is possible to move to a braking release position 2B (a position indicated by an imaginary line in FIG. 1).

  Here, the center point of the pivot shaft 3 is 3A, the contact position of the surface 4a of the brake lining 4 with the outer peripheral surface 10a of the rotating shaft 10 is 4A, and a line segment B passing through these is drawn. On the outer peripheral surface 10a of the rotating shaft 10, the normal line drawn to the contact position 4A is C, and the angle between the line segment B and the normal line C is α. Further, the friction angle between the outer peripheral surface 10a of the rotating shaft 10 and the brake lining 4 is β. In this example, the shapes of the tip end portion 2a and the arm portion 2b of the brake lever 2 are set so as to satisfy the relationship of α <β.

  In the brake device 1 having this configuration, in a normal state, the brake lever 2 is held at a braking position 2A indicated by a solid line in FIG. 1 by the spring force of the tension coil spring 5, and the brake lining 4 is rotated by a predetermined pressing force. 10 is pressed against the outer peripheral surface 10a. Therefore, when the rotating shaft 10 is about to rotate, a predetermined holding torque acts to hold the rotating shaft 10 at a predetermined rotational position.

  Here, in this example, the angle α is set to be smaller than the friction angle β. Therefore, when the rotating shaft 10 rotates in the direction indicated by the arrow A in FIG. 1, a self-boosting action works, and the outer peripheral surface 10 a of the brake lining 4 and the rotating shaft 10 is applied by the pressing force due to the spring force of the tension coil spring 5. A braking force larger than the frictional force generated between the rotating shaft 10 and the rotating shaft 10 is applied. As a result, when the rotating shaft 10 tries to rotate in the direction of the arrow A, a large holding torque acts and the rotation of the rotating shaft 10 is reliably prevented.

  When the actuator 6 is driven in this braking state, the brake lever 2 is rotated to the braking release position 2B indicated by an imaginary line. As a result, the brake lining 4 affixed to the tip end portion 2a of the brake lever 2 is separated from the outer peripheral surface 10a of the rotary shaft 10, and the rotary shaft 10 is switched to a state where the braking force is released. When the drive of the actuator 6 is stopped, it returns to the braking state again.

  In addition, the layout of each member of the brake device 1 shown in FIG. 1 is an example, and other layouts can be adopted. In addition, the brake lever 2 may have a different shape depending on the layout change. Furthermore, an elastic member for generating a braking force other than the tension coil spring 5 can be used. As the actuator 6, a linear motion mechanism driven by an electric motor, an electromagnetic plunger, or the like can be used, and a fluid pressure cylinder such as a hydraulic cylinder can also be used.

DESCRIPTION OF SYMBOLS 1 Brake device 2 Brake lever 2a Front-end | tip part 2b Arm part 2c Rear-end part 3 Rotation spindle 4 Brake lining 4a Surface 4A Contact position 5 Tension coil spring 6 Actuator 10 Rotating shaft 10a Outer peripheral surface

Claims (1)

A brake lever (2) rotatable about a predetermined pivot (3);
A brake lining (4) attached to the brake lever (2);
The brake lever (2) is rotated about the rotation support shaft (3), and the brake lining (4) is pressed against the outer peripheral surface (10a) of the rotation shaft (10) to be braked. A holding elastic member (5) held at the braking position (2A),
The brake lever (2) is rotated in the reverse direction about the rotation support shaft (3), so that the brake lining (4) is separated from the outer peripheral surface (10a) of the rotation shaft (10). An actuator (6) to be moved to the brake release position (2B)
The brake lining (4) is a flat plate having a constant thickness,
The contact position of the center the relative (3A) and said outer peripheral surface (10a) brake lining (4) of the rotation shaft (3) (4A) and a line segment passing through (B) are abutting position (4A ) With respect to the normal line (C) of the outer peripheral surface (10a) drawn to the rotation axis (10),
If the angle formed by the line segment (B) and the normal line (C) is α and the friction angle of the brake lining (4) with respect to the outer peripheral surface (10a) of the rotating shaft (10) is β, α <β A negative-acting brake device (1) characterized by satisfying the relationship:

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