JPH07205774A - Brake device for work vehicle - Google Patents

Abstract

PURPOSE:To improve operability of a parking brake by providing an intermediate shaft for supporting a link mechanism, capable of actuating an axle brake, by a parking brake lever, on a supporting bracket, providing an interlocking member for interlocking the intermediate shaft and the axle brake and providing an interlocking member for interlocking the intermediate shaft and the parking brake lever. CONSTITUTION:Axle brakes B, B of a rear wheel are used to concurrently serve as a side brake and a parking brake, and a brake device is provided with a foot operating system of operating the axle brakes BB by side brake pedals 41, 41 and a parking operating system of simultaneously operating both the axle brakes BB by a parking brake lever 51 through a lin mechanism A. The link mechanism A is constituted of operating rods 56, 56 for interlocking an intermediate shaft 55 and right/left brake levers 53, 53 and a connecting rod 57 for interlocking the parking brake lever 51 and the intermediate shaft 55. The intermediate shaft 55 is supported over to a pair of supporting brackets 58, 58 for a seat support vertically provided from a cylinder case 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking system for a work vehicle having left and right axle brakes such as a tractor and a carrier, and more particularly to a rational construction of an operating system for a parking brake.

[0002]

2. Description of the Related Art For example, a tractor disclosed in Japanese Utility Model Laid-Open No. 3-35880 and Japanese Utility Model Laid-Open No. 64-16931 has a pair of left and right brake pedals for operating left and right axle brakes. The brakes can be operated independently to enable the turning of the brakes, and the left and right brake pedals can be simultaneously depressed to act as a brake for traveling.

[0003]

When the axle brake having the above-mentioned structure is used as a parking brake, it is actually opened.
-16931 and Japanese Utility Model Laid-Open No. 63-162674, by providing a lock operation tool capable of locking the brake pedal at the depressed position, first, the left and right brake pedals are simultaneously depressed, and then the lock is performed. This is to operate the operation tool to maintain the brake pedal in the depressed position, that is, to use the foot brake as a parking brake.

However, there is a voice that it is easier to operate a vehicle with a dedicated parking brake lever like an automobile, and it is necessary to newly design the parking brake lever. The purpose of the present invention is to
In a work vehicle equipped with left and right independent brake pedals, while also using the axle brake as braking means during parking,
The point is that a dedicated parking brake lever is provided so that it can be reasonably linked to the axle brake.

[0005]

In order to achieve the above object, the present invention is provided with an axle brake located on each of the left and right sides of a mission case, and a pair of brake pedals which can individually operate the axle brake. A pair of left and right support brackets for seat supports that are erected from the transmission case are provided with a linkage mechanism that can simultaneously operate the left and right axle brakes by operating a single parking brake lever And a left-right interlocking member that interlocks and connects the intermediary shaft and the left and right axle brakes, and an interlocking member that interlocks and connects the intermediary shaft and the parking brake lever. It is characterized by being.

[0006]

Since the left and right axle brakes are operated by a single parking brake lever, a linkage mechanism for distributing the operation force is required in the middle of the operation system. In the present invention, the operation input at one location is converted into the operation output at two locations by using the left and right intermediate shafts, and the intermediate shaft is supported over the support bracket for the seat support. That is, since the existing bracket is used to support the intermediate shaft, a new support member is not required. Also, the foot brake operation system by the brake pedal is arranged at a relatively low position below the floor of the driving part, whereas the parking brake operation system is for the seat support located above the mission case. Is provided at a relatively high position passing through the support bracket portion of
Brake operation systems do not interfere or get complicated, and operation system layout requires less effort.

[0007]

[Effects of the Invention] Therefore, by devising the dual use of the members by effectively using the existing parts, it is possible to equip a dedicated parking brake lever without making a large modification, and contribute to the operability of the parking brake rationally. It was possible to provide a braking device that operates.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following is a description of the embodiments of the present invention applied to a tractor, which is an example of a work vehicle, with reference to the drawings. As shown in FIG. 1, an engine 3, a hydrostatic continuously variable transmission (hereinafter abbreviated as HST) 4, and a gear transmission (see FIG. An agricultural tractor is configured by including a mission case 5 in which (not shown) and the like, a driving section C, and the like are provided.

Next, the structures of the forward speed change pedal 6 and the reverse speed change pedal 7 for changing the speed of the hydrostatic HST 4 for traveling will be described. As shown in FIG. 4 and FIG.
A circular vibration-proof weight 10 is attached to the trunnion shaft 4a of ST4 via a vibration-proof rubber 51. HS
A roller 11a of an arm 11 supported so as to be vertically swingable around a horizontal axis P1 of T4 is abutted from below on a guide plate 10a fixed to a weight 10, and an arm 11 is attached to an upper side by a spring 12. The weight 10 and the trunnion shaft 4a are urged back to the neutral position.

As shown in FIGS. 4, 10 and 11, the forward speed change pedal 6 is fixed to the cylindrical member 8 in the forward direction, the reverse speed change pedal 7 is fixed in the backward direction, and the operating arm 9 is further attached to the cylindrical member 8. It is fixed. On the other hand, the flat plate is bent in a U shape and fixed to the machine body frame 13 to form a pair of support brackets 14.

As a result, the cylindrical member 8 to which the forward and reverse speed change pedals 6 and 7 are fixed is inserted between the pair of support brackets 14, and the support pin 15 is inserted into the support holes 14a of the pair of support brackets 14 and the cylinder. Insert over member 8. Then, the lateral piece 14 of the support bracket 14 on the outside of the machine body
The roll pin 16 is inserted from above into the opening 14c of b, and this roll pin 16 is inserted into the opening 15a of the support pin 15. Therefore, the forward and reverse speed change pedals 6, 7 are supported swingably up and down around the support pin 15.
The roll pin 16 prevents the support pin 15 from coming off and from rotating.

With the above structure, when the forward and reverse speed change pedals 6 and 7 are attached to the support bracket 14, the operating arm 9 of the cylindrical member 8 and the weight 1 are attached as shown in FIG.
The operation arm 10b fixed to 0 is connected by a link 17. Accordingly, by depressing the forward speed change pedal 6 and the reverse speed change pedal 7, the HST 4 is speed-changed to the forward side and the reverse side via the weight 10.

In this agricultural tractor, the speed change lever 18 is also configured so that the speed change operation of the HST 4 can be performed. Next, the structure of the speed change lever 18 will be described. Figure 1,
As shown in FIGS. 2 and 3, a pair of left and right lift arms 20 are vertically swingably supported by a cylinder case 19 fixed to the rear upper surface of the mission case 5, and the lift arms 20 are vertically swingably driven. (Not shown) is housed in the cylinder case 19. As shown in FIGS. 8, 3 and 2, a support shaft 21 and a cylindrical member 31 are fixed to a lateral side portion of the cylinder case 19 on the left side of the machine body, and a lever arm 22 is rotatably supported by the cylindrical member 31. A gear shift lever 18 is swingably supported around an axis P2 at the tip of the lever arm 22.

An arm 23 is attached to the boss portion of the lever arm 22.
a and 23b are integrally and rotatably supported, and one arm 23a is in contact with the lever arm 22 from below,
As shown in FIGS. 2, 3 and 4, the arm 23b on the left side of the machine body,
The operation arm 10b of the HST 4 on the right side of the machine body is interlockingly connected by a linking rod 24, a linking shaft 25 to which a pair of arms 25a and 25b are fixed, and a linking rod 26.

With the above structure, as shown in FIGS. 3, 2 and 4, when the speed change lever 18 is operated from the neutral position N toward the forward position F along the lever guide 38, the lever arm 22 moves to the arm 23a. By pushing, the HST 4 is shifted from the neutral position to the forward high speed side. Then, as shown in FIG. 4, a damper 39 for suppressing a sudden operation of the speed change lever 18, the forward and reverse speed change pedals 6, 7 is attached to the arm 25b.

In this agricultural tractor, the speed change lever 18 is frictionally held so that the vehicle can run at a constant speed. Next, the structure for holding the speed change lever 18 with friction will be described. As shown in FIG. 8, a plurality of first friction plates 2
7, the second friction plate 28 and the third friction plate 29 are alternately superposed and fitted on the cylindrical member 31, and the first friction plate 27 is connected to the pin 22a of the lever arm 22.
The lever arm 22 and the respective first friction plates 27 are integrally formed into the support shaft 2.
I am trying to rotate around 1. Each second friction plate 28 is connected and fixed to a pin 30a fixed to a support plate 30.

As shown in FIGS. 8 and 9, a cylindrical member 31
A ring-shaped holding member 32 is rotatably fitted to the outside of the cylindrical member 31, and a pair of slanted inclined holes 31 is formed in the cylindrical member 31.
The bolt 33 of the holding member 32 is inserted in a. As shown in FIGS. 3, 9 and 1, a hook rod 36 is attached to a support bracket 58 fixed to the cylinder case 19 via a pair of nuts 35. The hook rod 36 and the arm 32 a of the holding member 32 are connected to each other. A tension spring 37 is installed over the entire length.

Therefore, when the holding member 32 is biased by the biasing force of the tension spring 37 so as to rotate in the clockwise direction of the paper surface of FIG. 9, the inclined hole 31a and the bolt 33 of FIG. The holding member 32 pushes the first, second and third friction plates 27, 28 and 29 in an attempt to move to the right in the plane of FIG. 8, and the lever arm 22 and the speed change lever 18 are frictionally held. In this case, as shown in FIGS. 1, 3 and 9, the bracket 34 and the nut 35 are located below the rear surface of the driver's seat 40.
It is exposed to the rear. Accordingly, the nut 35 is rotated from the rear side of the machine body, and the fixing position of the hook rod 36 is adjusted along the left-right direction of the paper surface of FIG. 9 (the longitudinal direction of the tension spring 37).
7, the lever arm 22 and the shift lever 1
It is possible to adjust the friction holding force of No. 8 strongly.

With the above structure, when the speed change lever 18 is operated from the neutral position N toward the forward position F against the friction holding force of the holding member 32, the forward and reverse speed change pedals are interlocked with this operation. 6, 7 and HST4 are operated toward the high speed side of the forward movement, and the shift lever 18 is moved to the desired position.
When the hand is released from, the gear shift lever 18, the forward and reverse gear shift pedals 6, 7,
The HST 4 is held at that position, and the aircraft runs at a constant speed.

If you want to accelerate temporarily in this state,
It suffices to depress the forward speed change pedal 6, and this operation can be performed without any trouble because the arm 23a in FIG. 3 separates from the lever arm 22 downward in the drawing. Then, when the forward release pedal 6 is released after the temporary acceleration, as shown in FIG.
By the action of the arm 11 of the
The HST 4 and the forward speed change pedal 6 are stopped at the original position where the arm 23a of FIG. 3 contacts the lever arm 22, and the original traveling state at a constant speed is restored.

When it is desired to change the above-mentioned constant speed to the high speed side, it suffices to operate the speed change lever 18 to the high speed side of the forward drive position F against the friction holding force of the holding member 32. If you want to change to the side, holding member 32
Against the friction holding force by the gear shift lever 18 to the forward position F
It is sufficient to operate the shift lever 18 toward the low speed side of the forward drive position F by operating the reverse speed change pedal 7 by depressing the reverse speed shift pedal 7.

When it is desired to move the vehicle backward, contrary to the above state, first, the gear shift lever 18 located at the neutral position N in FIG. 3 is operated to the maximum speed on the backward position R side. In this case, the forward and reverse speed change pedals 6, 7 and HST4 remain in the neutral position due to the action of the arm 11 in FIG. 5, and then the reverse speed change pedal 7 is depressed to shift the HST 4 to the reverse side. When moving backward, the vehicle cannot run at a constant speed by the speed change lever 18 as when moving forward. If the foot is released from the speed change pedal 7 for reverse movement, the arm 11 of FIG. Return to neutral position.

As described above, the friction holding of the speed change lever 18 is automatically released when the machine is stopped while the vehicle is traveling at a constant speed while holding the speed change lever 18 frictionally. Next, the configuration of this cancellation will be described. This agricultural tractor is provided with a pair of left and right axle brakes B capable of independently braking the left and right rear wheels 2, and is mechanically connected to the left and right axle brakes B, B as shown in FIGS. 4 and 6. Left and right side brake pedals 4
1, 41 are provided. A pair of links 42 are swingably supported around the axis P3 of the left and right side brake pedals 41, the lower ends of the left and right links 42 are pin-connected, and the rollers 43 are attached to the pin connecting portions. There is.

On the other hand, the operating member 44 obtained by bending the flat plate into a mountain shape (see FIG. 6) is used as the horizontal axis P of the machine body frame 13.
4 is swingably supported around 4, and is urged upward by a spring 45, and is stopped by a stopper 46 in the posture shown in FIG. Then, as shown in FIGS. 4 and 3, the operation member 4
The wire 47 is connected across the four arms 44a and the arm 32a of the holding member 32. Further, as shown in FIGS. 3 and 8, a spring 48 is connected across the lever arm 22 and the bracket 34, and the transmission lever 18 is biased to the neutral position N side of the lever guide 38.

With the structure described above, when the left and right side brake pedals 41 are simultaneously stepped on while the vehicle is traveling at a constant speed while frictionally holding the speed change lever 18, as described above, the operation of stopping the machine body is performed. As shown in FIG. 5 and FIG. 6, the left and right links 42 and the roller 43 move substantially right below and push the operation member 44 downward. This allows the wire 4
7 is pulled toward the operation member 44 side, and the holding member 32 is rotated counterclockwise in FIG.
By the cam action of the inclined hole 31a and the bolt 33, the holding member 32 is operated so as to be separated from the first friction plate 27 and the like to the left in the drawing of FIG.

Therefore, the friction holding force by the holding member 32 disappears, and the gear shift lever 18 is returned from the forward movement position F side to the neutral position N by the action of the spring 48 as shown in FIG. Since it hits the corner of N and stops, the forward and reverse speed change pedals 6, 7 and HST4 return to the neutral position by the action of the arm 11 in FIG. As shown in FIGS. 4 and 5, the operation piece 44 b of the operation member 44.
The limit switch 49 is in contact with the limit switch 4 and the left and right side brake pedals 41 are simultaneously depressed as described above, and the operating piece 44b of the operating member 44 is operated by the limit switch 4.
The brake lamp 50 is configured to light up when it is moved downward from the position 9.

In the case of turning around a ridge, the front wheel 1 is steered and at the same time, the rear brake 2 is turned by the side brakes on the turning center side.
May brake and make a small turn. In this case, as shown in FIG. 7, for example, even if the side brake pedal 41 on the left side of the paper surface is depressed, the axis P3 of the link 42 on the right surface of the paper surface does not move downward, so that the roller 43 follows the upper surface of the operation member 44. And the operating member 44 is not operated downward. As a result, as described above, when the front wheel 1 is steered and one of the side brake pedals 41 is depressed while the vehicle is traveling at a constant speed while frictionally holding the speed change lever 18, the friction holding force of the speed change lever 18 is exerted. Does not disappear, and a small turn can be performed at a constant speed while frictionally holding the speed change lever 18.

Next, the above-mentioned axle brake will be described in more detail. The friction multiple disc type axle brakes B, B for the pair of left and right rear wheels 2 are also used as side brakes and parking brakes. That is, as shown in FIGS. 1, 3, and 4, a foot operating system for operating the axle brakes B, B with the left and right side brake pedals 41, 41, and both axle brakes B, with one parking brake lever 51. A parking operation system for simultaneously operating B is provided.

As shown in FIG. 12, the foot operating system has a single operating shaft 52 with respect to the left side brake pedal 41.
With the right side brake pedal 41
And the left and right axle brakes B and B of the L-shaped brake levers 53 and 53, respectively.
The operating shaft 52 and the right side brake pedal 41 are interlockingly connected by interlocking rods 54, 54, respectively.

As shown in FIG. 13, the parking operation system includes a parking brake lever 51 provided on the right side of the driver's seat 40.
And a linkage mechanism A capable of simultaneously operating the left and right axle brakes B, B by operating the parking brake lever 51. The linkage mechanism A includes the intermediate shaft 55 and the intermediate shaft 55.
And an operating rod (corresponding to an interlocking member) 56 and 56 for interlocking and connecting the left and right brake levers 53 and 53, and a connecting rod (corresponding to an interlocking member) 57 for interlocking and connecting the parking brake lever 51 and the intermediate shaft 55. It is configured. Incidentally, FIG.
The right link boss 61 shown in FIG.
The rod connecting pieces at some locations are drawn as having a shape overlapping with each other in a side view (a shape different from that in FIG. 13).

As shown in FIG. 14, the intermediate shaft 55 is a cylinder case 19 (which is a part of the mission case 5c).
Is a shaft extending in the left and right direction over a pair of left and right support brackets 58, 58 for seat support which are erected from the driver seat 40 to the connecting member 59 for integrally connecting the left and right support brackets 58, 58. The support frame 40f is attached via a cushion rubber 34 so as to form a vibration-proof mount structure. The intermediate shaft 55 and the left and right operation rods 56,
56 is interlockingly connected via left and right link bosses 60 and 61 which are pin-connected to the intermediate shaft 55, and a connecting rod 57 is connected to the right link boss 61 among them.

The operation rods 56, 56 and the brake levers 53, 53 are interchangeably connected by a long hole and a pin, and the side brake pedals 41, 41 are independent side brakes without the parking brake lever 51 moving together. The foot brake can be operated by the pedals 41, 41. Further, the interlocking rods 54, 54 and the brake levers 53, 53 are interchangeably connected by the long holes and the pins, and the parking brake lever 51 can perform the parking brake operation without the side brake pedals 41, 41 moving together.

Next, the headlights will be described. Figure 1
In the specification without a cabin shown in Fig. 15, the headlight 63 is mounted only on the front part of the engine hood 64, but in the case with the cabin 62 shown in Fig. 15, the headlight 65 is also mounted on the front part of the cabin 62. ing. In the specification without a cabin, as shown in FIG. 16, an electric circuit is constituted by a double filament type headlight 63 capable of switching between a low beam and a high beam, and a changeover switch 66, and a lead beam 67 for the high beam has a hollow 68. Is equipped with. In this circuit, if the switch is operated to Lo, the headlight 63 becomes low beam light, and if it is operated to Hi, the headlight 63 becomes high beam light.

In the specification with the cabin 62 shown in FIG. 17, an electric circuit is constituted by the lower headlight 63 of the bonnet 64, the upper headlight 65 of the single filament type, and the changeover switch 66, and the specification without the cabin is provided. Giboshi 68
Is connected to the lead wire of the upper headlight 65. In this case, if the switch 66 is operated to Lo, only the lower headlight 63 is turned on, and if it is operated to Hi, only the upper headlight 65 is turned on. That is, even if the specification of the presence or absence of the cabin 62 is changed, it is only necessary to change the connection of the bullet 68 arranged below the driver's seat 40, and the wiring itself can be commonly used.

[Other Embodiments] The intermediate shaft 55 and the parking brake lever 51 or the brake lever 53 may be interlockingly connected by a wire, and the wire, rod, etc. are collectively referred to as "interlocking member".
Express.

It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the structures of the accompanying drawings by the entry.

[Brief description of drawings]

1] Overall side view of an agricultural tractor

FIG. 2 is a front view near the shift lever and HST.

FIG. 3 is a side view near the base of the speed change lever.

FIG. 4 is a side view showing the vicinity of a shift pedal and a brake operation system.

FIG. 5 is a side view near the side brake pedal and the trunnion shaft of the HST.

FIG. 6 is a front view near the side brake pedal.

FIG. 7 is a front view showing a state in which one side brake pedal is depressed.

FIG. 8 is a vertical sectional front view of the vicinity of a holding member that frictionally holds a shift lever.

FIG. 9 is a vertical sectional side view in the vicinity of a holding member that frictionally holds a shift lever.

FIG. 10 is a vertical cross-sectional front view of the vicinity of a support bracket that supports the forward and reverse speed change pedals.

FIG. 11 is an exploded perspective view of forward and reverse speed change pedals, a support bracket, and the like.

FIG. 12 is an exploded perspective view showing the structure of a foot operating system.

FIG. 13 is an exploded perspective view showing the structure of a parking operation system.

FIG. 14 is a front view showing a support structure for an intermediate shaft.

FIG. 15 is a side view of a tractor with a cabin.

FIG. 16 is a circuit diagram showing a headlamp wiring structure without a cabin.

FIG. 17 is a circuit diagram showing a headlamp wiring structure of a specification with a cabin.

[Explanation of symbols]

 5c Mission case 41 Brake pedal 51 Parking brake pedal 55 Intermediate shaft 56 Interlocking member 57 Interlocking member 58 Support bracket A Linkage mechanism B Axle brake

Claims (1)

[Claims] 1. An axle brake (B) located on each of the left and right sides of a mission case (5c), and a pair of brake pedals (41), (41) capable of operating the axle brakes (B), (B) separately. And a linkage mechanism (A) capable of simultaneously operating the left and right axle brakes (B) and (B) by operating a single parking brake lever (51) arranged in the driving section (C). , This linkage mechanism (A)
A pair of left and right support brackets (58), (5) for seat support which are erected from the mission case (5c).
8) a horizontal intermediate shaft (55) that is supported over 8),
The intermediate shaft (55) and the left and right axle brakes (B),
Left and right interlocking members (56), (5) interlockingly connecting with (B)
6) and a braking device for a work vehicle, which is configured by an interlocking member (57) interlockingly connecting the intermediate shaft (55) and the parking brake lever (51).