JP2004183890A - Brake device of reach-type forklift - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brake device of a reach type forklift which is easily assembled and generates less noise. <P>SOLUTION: An elastic member 48 to bring an armature 32 into contact with a lining 30 by the urging force is provided. The elastic member 48 is a coil spring, a slide pin 40 is erected from the armature 32, a sliding hole 42 with the slide pin 40 slidably inserted therein is formed in a wheel 20, and the elastic member 48 is accommodated in the slide hole 42. The urging force of the elastic member 48 is determined so that the armature 32 is slightly brought into contact with the lining 30. The braking force is generated by pressing the armature 32 against the lining 30 by the attraction of an electromagnet 26. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a reach type forklift brake device that generates a braking force by pressing an armature against a lining by the attraction of an electromagnet.

Conventionally, in a reach type forklift, as described in Patent Document 1, a brake device is also provided on a front wheel which is a driven wheel, for example, a load applied to a rear wheel side when a load is loaded is reduced, and braking on a rear wheel side is performed. In order to prevent a situation in which sufficient braking cannot be obtained, there has been proposed a vehicle in which the front wheels are braked during braking to shorten the braking distance.
JP-A-13-151494 (FIG. 9 on page 6)

  However, in such a conventional device, it is necessary to properly assemble the gap between the electromagnet and the armature, so that the assembly is troublesome, and if it is not assembled in an appropriate gap, it causes noise. Further, when the wear of the armature or the like of the brake device that is repeatedly used progresses, there is a problem that a gap increases by an amount corresponding to the wear, which causes noise.

  An object of the present invention is to provide a reach type forklift brake device which is easy to assemble and generates less noise.

In order to achieve the object, the present invention has taken the following means to solve the object. That is,
In a brake device for a reach-type forklift that generates a braking force by pressing a slidable armature against a lining by the attraction of an electromagnet, a contact mechanism for constantly contacting the armature with the lining is provided. That is the braking device.

  The contact mechanism may press the armature in a sliding direction to make contact with the lining. Further, the contact mechanism may be configured to lightly contact the armature with the lining by attracting the electromagnet. Further, the contact mechanism may include an elastic member that makes the armature lightly contact the lining by an urging force. The elastic member may be a coil spring. The contact mechanism may be one in which a slide pin is erected on the armature, a slide hole in which the slide pin is slidably inserted is provided in the wheel, and the elastic member is housed in the slide hole. The wheel may be a front wheel of a reach-type forklift.

  As described above, the reach type forklift brake device of the present invention brings the armature into contact with the lining by the attraction of the electromagnet or the urging force of the elastic member. This makes it easier to suppress noise during suction.

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.
As shown in FIG. 2, reference numeral 1 denotes a reach-type forklift, and a pair of outriggers 2 are provided in front of the reach-type forklift 1 in the vehicle. A mast 6 that supports a pair of left and right forks 4 is movably provided between the pair of outriggers 2. A front wheel 8 is provided at a front end of the pair of outriggers 2, a machine base 10 is provided at a rear portion of the vehicle, and a rear wheel 12 is provided.

  As shown in FIG. 1, the front wheel 8 is supported by a support shaft 14 that protrudes horizontally from the outrigger 2. A pair of bearings 16 and 18 are fitted on the support shaft 14, and a wheel 20 is fitted on the outer periphery of the bearings 16 and 18, and the wheel 20 is rotatably supported by the support shaft 14. The bearing 18 is prevented from coming off by a nut 22 screwed to the support shaft 14. A tire 24 is fitted on the outer periphery of the wheel 20.

  A ring-shaped electromagnet 26 disposed around the support shaft 14 is fixed to the outrigger 2 so as to face the wheel 20. The electromagnet 26 has a built-in coil 28 and a lining 30 facing the wheel 20. A ring-shaped armature 32 is disposed between the electromagnet 26 and the wheel 20.

  The armature 32 has a torque pin 34 erected on the wheel 20 side. An insertion hole 36 into which the torque pin 34 is inserted is formed in the wheel 20, and the torque pin 34 can slide in the insertion hole 36 in the axial direction. The plurality of torque pins 34 and the insertion holes 36 are provided on the same circumference. In addition, a bush as a slide bearing may be provided between the insertion hole 36 and the torque pin 34.

  A slide pin 40 is provided on the armature 32 on the wheel 20 side in parallel with the torque pin 34. The wheel 20 has a slide hole 42 into which the slide pin 40 is slidably inserted. The sliding hole 42 is formed through the wheel 20, and a cover 44 is fixed to the outside of the wheel 20 with a bolt 46, and the sliding hole 42 is closed.

  An elastic member 48 is accommodated in the slide hole 42 between the slide pin 40 and the cover 44. In the present embodiment, a coil spring is used for the elastic member 48, but is not limited to this, and may be made of rubber or sponge. The elastic member 48 is compressed and accommodated in the sliding hole 42, and the armature 32 is urged toward the lining 30 via the slide pin 40 by the urging force of the elastic member 48.

  With this bias, the armature 32 is configured to come into contact with the lining 30. This contact only needs to touch the lining 30 lightly, and even if the armature 32 contacts the lining 30 due to the urging force of the elastic member 48, the elastic member is so arranged that the friction between the armature 32 and the lining 30 is as small as possible. 48 biasing forces are set.

  When the armature 32 or the lining 30 is worn, the armature 32 is pushed by the urging force of the elastic member 48 and moves to maintain the contact with the lining 30, but the movement changes the length of the elastic member 48. However, the smaller the spring constant, the better the change in the biasing force is. In the present embodiment, the elastic member 48 has a spring constant set to 0.1 N / m and an urging force set to 100 g.

  Incidentally, the elastic member 48 may be set by an experiment or the like. Also, a plurality of sets of the slide pins 40, the slide holes 42, and the elastic members 48 are provided on the same circumference at equal intervals, and three sets in the present embodiment. Further, the slide pin 40 may be configured to also serve as the torque pin 34. In the present embodiment, the contact mechanism A is constituted by the slide pin 40, the slide hole 42, the cover 44, the bolt 46, and the elastic member 48.

Next, the operation of the brake device of the reach type forklift according to the present embodiment will be described.
When the coil 28 of the electromagnet 26 is energized by excitation, the armature 32 is attracted to the lining 30. When the armature 32 is pressed against and adhered to the lining 30 by the electromagnetic force, a braking torque is transmitted to the wheel 20 via the torque pin 34, and the front wheel 8 is braked.

  Since the armature 32 is in contact with the lining 30 by the urging force of the elastic member 48, the movement of the armature 32 when the electromagnet 26 is excited is almost zero. Therefore, even when the electromagnet 26 is excited and braked, no contact sound of the armature 32 to the lining 30 is generated.

  At the time of non-excitation of the electromagnet 26 in which the energization of the coil 28 is stopped, the attraction of the armature 32 to the lining 30 is released, and the braking of the front wheel 8 is released. Even in the released state, the armature 32 is in contact with the lining 30 by the urging force of the elastic member 48. Even if the front wheel 8 rotates in a state where the armature 32 and the lining 30 are in contact with each other, the urging force is very small, so the friction between the armature 32 and the lining 30 is small, and there is almost no braking force. The amount of wear of the armature 32 and the lining 30 due to contact is also very small.

  When braking is repeated, the lining 30 and the armature 32 wear. Even when worn, the armature 32 is kept in contact with the lining 30 by the biasing force of the elastic member 48, and the gap d between the armature 32 and the side surface of the wheel 20 increases.

  On the other hand, at the time of assembling, the assembling can be performed without controlling and adjusting the gap between the armature 32 and the lining 30. Since the armature 32 is brought into contact with the lining 30 by the biasing force of the elastic member 48, no special adjustment is required, so that the assembly is easy.

  Next, a brake device for a reach type forklift according to a second embodiment different from the above-described embodiment will be described with reference to FIG. Note that the same members as those in the above-described embodiment are denoted by the same reference numerals, and detailed description is omitted.

  In the second embodiment, the armature 32 is brought into contact with the lining 30 by controlling the attractive force of the electromagnet 26 instead of the urging force of the elastic member 48. As shown in FIG. 3, a switching circuit 50 is connected to the coil 28 of the electromagnet 26, and a brake current circuit 52 and a contact current circuit 54 are connected to the switching circuit 50.

  The switching circuit 50 is a circuit for selectively connecting the brake current circuit 52 or the contact current circuit 54 and the coil 28. The switching circuit 50 connects the brake current circuit 52 and the coil 28 during braking, and connects the contact current circuit 54 and the coil 28 during non-braking. 28. The brake current circuit 52 applies a current to the coil 28 to attract the armature 32 and generate an electromagnetic force required for braking. The contact current circuit 54 applies a weak current to the coil 28 such that the armature 32 is sucked and lightly contacts the lining 30.

  In the second embodiment, the switching circuit 50 connects the brake current circuit 54 and the coil 28 to brake the front wheels 8 during braking, as in the above-described embodiment. At the time of non-braking, the switching circuit 50 connects the contact current circuit 54 and the coil 28 to lightly contact the armature 32 with the lining 30. Therefore, even if the electromagnet 26 is excited and braked, the armature 32 moves to the lining. No contact noise is generated.

  In the second embodiment, the switching circuit 50, the brake current circuit 52, and the contact current circuit 54 are configured as a contact mechanism B. In the second embodiment, the switching circuit 50 and the contact current circuit 54 energize the coil 28 to lightly contact the armature 32 with the lining 30. In particular, the switching circuit 50 and the contact current circuit 54 provide the energization. Instead, the armature 32 can be lightly brought into contact with the lining 30 by the contact mechanism by the residual magnetism when the electromagnet 26 is braked. However, when this residual magnetism is used, since the residual magnetism disappears relatively quickly after the brake is turned off, a very frequent getting-on / off and forward-backward switching operation in which the brake is repeatedly turned on and off frequently is used. Applicable to reach type forklifts.

  The present invention is not limited to such an embodiment at all, and can be implemented in various modes without departing from the gist of the present invention.

It is an expanded sectional view of the brake device provided in the front wheel of the reach type forklift as one embodiment of the present invention. It is a side view of the reach type forklift of this embodiment. It is an expanded sectional view of the brake device provided in the front wheel of the reach type forklift as a 2nd embodiment.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 ... Reach type forklift 2 ... Outrigger 4 ... Fork 6 ... Mast 8 ... Front wheel 10 ... Machine base 12 ... Rear wheel 14 ... Support shaft 16, 18 ... Bearing 20 ... Wheel 24 ... Tire 26 ... Electromagnet 28 ... Coil 30 ... Lining 32 .. Armature 34 Torque pin 36 Insert hole 40 Slide pin 42 Sliding hole 44 Cover 48 Elastic member 50 Switching circuit 52 Brake current circuit 54 Contact current circuit

Claims (7)

In a reach-type forklift brake device that generates a braking force by pressing a slidable armature against a lining by the attraction of an electromagnet,
A brake device for a reach-type forklift, comprising a contact mechanism for constantly bringing the armature into contact with the lining. The brake device for a reach-type forklift according to claim 1, wherein the contact mechanism presses the armature in a sliding direction to contact the lining. The brake device for a reach type forklift according to claim 2, wherein the contact mechanism causes the armature to lightly contact the lining by attracting the electromagnet. The brake device for a reach-type forklift according to claim 2, wherein the contact mechanism has an elastic member that makes the armature lightly contact the lining by an urging force. The brake device for a reach type forklift according to claim 4, wherein the elastic member is a coil spring. The contact mechanism is characterized in that a slide pin is erected on the armature, a slide hole in which the slide pin is slidably inserted is provided in the wheel, and the elastic member is housed in the slide hole. The brake device for a reach type forklift according to claim 4 or 5. The brake device for a reach type forklift according to claim 6, wherein the wheel is a front wheel of a reach type forklift.

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