JPH01240350A - Car brake device - Google Patents

Abstract

PURPOSE:To help the braking force by controlling so as to cause connection with a hydraulic clutch in slip condition at the operating time of a drive brake in an arrangement where two sets of transmission including friction type hydraulic clutch with different gear ratios in the running power transmitting system are provided parallelly. CONSTITUTION:A running power transmitting system 19 has a running transmission 20 and a rear wheel differential 21 interlocked therewith through a bevel pinion shaft 22 and performs transmission to the left and right rear wheels 14 via a final speed reducing device 24. A front wheel drive system 27 has a high/low speed switching device 30 to transmit rotation of a transmission shaft 29 interlocked with the mentioned bevel pinion shaft 22 through a gear train 28 to a propeller shaft 31, and its rotation is transmitted to the left and right front wheels 10 via a front wheel differential 32 and a final speed reducing device 33. The high/low speed switching device 30 is composed of a low speed and a high speed transmission 35, 40 including hydraulic clutches 34, 36, which are so controlled as to be connected in slip condition while a rear wheel brake 25 is in application.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a braking device for a vehicle, which supplements and assists braking force by utilizing a transmission part in a traveling power transmission system.

(Prior Art) Vehicles such as agricultural tractors are provided with brakes for braking a pair of left and right rear wheels, which are driving wheels, and are operated to perform braking.

(Problems to be Solved by the Invention) Conventionally, braking force has been obtained simply by using the brakes, which has the disadvantage that the braking distance becomes long when the vehicle is traveling at a high speed and the inertial force is large. However, if the size of the brake is increased in order to secure braking force, there is a problem in that the manufacturing cost increases accordingly.

In view of such conventional problems, it is an object of the present invention to utilize components of a traveling power transmission system to assist braking force.

(Means for achieving the object) The present invention provides a driving power transmission system 19 as a means for achieving the object.
Inside, two sets of transmission parts 35.40 with different transmission ratios are provided in parallel, and a friction type hydraulic clutch 34.36 selects these two sets of transmission parts 35.40, and brakes the drive wheel I4. The vehicle is equipped with a control means 50 for connecting both clutches 34 and 36 in a slipping state when the brake 25 is activated.

(Operation) The brake pedal 26 is depressed to brake the rear wheel 14 using the brake 25. At this time, the hydraulic clutches 34, 36 in the traveling power transmission system 19 are connected in a slipping state, so that the two sets of transmission parts 35, 40 with different transmission ratios are simultaneously connected to the power transmission system 1.
9, thereby generating a braking force and assisting the braking force provided by the brake 25.

(Example) Hereinafter, the present invention will be described in detail with reference to the illustrated example.
In the figures and FIG. 4, reference numeral 1 denotes a tractor body, which includes an engine 2, a transmission case 31, and the like. 4 is engine 2
5 is the instrument panel at the rear, 6 is the bonnet that covers the
is the handle. A front axle case 7 is supported by a center shaft at the front of the tractor body 1, and a front wheel 10 is supported at both left and right ends of the front axle case 7 via a king pin 8, a front wheel case 9, etc. so as to be freely steerable. has been done. Reference numeral 11 denotes a steering cylinder for the front wheel 10, which is configured to operate left and right in conjunction with the handlebar 6, and to steer the front wheel 10 around the king pin 8 via a tie rod 12.

A turning angle detector 13 detects the turning angle of the front wheels 10, and is configured to turn on when the turning angle of the front wheels 10 becomes approximately 40 degrees or more during a turn.

Reference numeral 14 denotes left and right rear wheels, which are provided on both rear sides of the tractor body 1 via rear axle cases 15 and the like. 16 is a rear wheel fender, 117 is a driver's seat, and 18 is a step.

FIG. 1 shows a traveling power transmission system 19, in which 20 is a traveling transmission, and 21 is a transmission 20 via a bevel pinion shaft 22.
This is a rear wheel differential device that is linked to the transmission case 3, and these are built into the transmission case 3. The rear wheel differential device 21 is operatively connected to the left and right rear wheels 14 via a differential yoke shaft 23 and a final reduction gear 24, and drives each rear wheel 14. Brakes 25 are provided between the rear wheel differential device 21 and the final reduction gear device 24 so as to control the left and right rear wheels 14 via the respective differential yoke shafts 23 . The left and right brakes 25 can be operated independently or simultaneously by left and right brake pedals 26 arranged on the front side of the step 18.

27 is a front wheel drive system, which includes a transmission shaft 29 interlocked with the bevel pinion shaft 22 via a gear train 2B, and a high/low speed switching device 3.
0, a propeller shaft 31, a front wheel differential device 32, and a final reduction device 33, and the left and right front wheels 10 are driven by the power from the pinion shaft 22. The front wheel differential device 32, final reduction gear device 33, etc. are mounted on the front axle case 7,
It is incorporated into the front wheel case 9, etc.

The high-low speed switching device 30 includes a low-speed transmission section 35 that directly connects the transmission shaft 29 and the propeller shaft 31 with a transmission ratio of 1:1 via a low-speed hydraulic clutch 34, a high-speed hydraulic clutch 36, a gear train 37, an intermediate shaft 38, Transmission shaft 29 via gear train 39
and a high-speed transmission section 40 that interlocks and connects the propeller shaft 31 and the propeller shaft 31 at a transmission ratio of 1:2. The hydraulic clutches 34 and 36 are friction type, and when both hydraulic clutches 34 and 36 are disengaged, the front wheels 10 are in an idle state and the rear wheels 14 drive the two wheels, and when the low-speed hydraulic clutch 34 is engaged, the front wheels 10 are driven by the rear wheels 14. The four-wheel drive system rotates at a circumferential speed substantially in sync with the four-wheel drive system, and when the high-speed hydraulic clutch 36 is engaged, the front wheels 10 rotate at about twice the circumferential speed of the rear wheels 14, resulting in double-speed turning. 37.
38 is a pressure proportional electromagnetic valve that controls the hydraulic clutches 34 and 36, respectively, and has a solenoid 39 and a solenoid 40. 41 is a hydraulic pump. A speed detector 42 detects the rotation of the gear 43 of the gear train 29.

FIG. 2 shows the control circuit for the solenoid valves 37, 38. In FIG. 2, 44 is a brake switch that detects simultaneous operation of the left and right brake pedals 26. 45 is a speed discriminator,
When the brake switch 44 is turned on, the speed detector 42
The actual traveling speed is determined from the speed signal from the vehicle, and a high speed signal a is output when the vehicle is running at a high speed, and a medium speed signal is output when the vehicle is running at a medium speed. 46 is a function generator, and brake switch 4
4 is turned on, a function signal C is generated having a rise characteristic depending on the magnitude of the speed signal from the speed detector 42. It should be noted that the function signal C has a relationship such that the higher the traveling speed, the greater the rising characteristic. 47 is the drive part of the solenoid valve 37, and when there is a low speed signal, the function signal C
The solenoid 39 is driven so that a pressure proportional to is obtained. Reference numeral 48 denotes a drive unit for the electromagnetic valve 38, which drives the solenoid 40 so that a pressure proportional to the function signal C is obtained when there is a high speed signal a. A switching circuit 49 drives the solenoid 39 of the electromagnetic valve 37 when the turning angle detector 13 is off, and drives the solenoid 40 of the electromagnetic valve 38 when the turning angle detector 13 is on. In addition, the speed detector 42, the brake switch 44, the speed discriminator 45,
The function generator 46, drive units 47, 48, etc. constitute a control means 50 for the hydraulic clutch 34, 36, whereby the function signal C is set so that the hydraulic clutch 34, 36 is in a slipping state when the hydraulic clutch 34, 36 is connected. There is.

When driving on the road, the left and right brake pedals 26 are connected so that they can be operated simultaneously. Therefore, in a two-wheel drive state where the rear wheels 14 are driven to drive the vehicle, when the vehicle stops traveling, when the brake pedal 26 is depressed, the left and right brakes 25 are actuated to brake the left and right rear wheels 14 .

At this time, if the vehicle is traveling at high speed, the speed discriminator 45 determines the speed signal from the speed detector 42 and outputs the high speed signal a, so that the high speed signal a is input to the drive units 47 and 48.

On the other hand, the function generator 46 generates a function signal C according to the speed signal, and this is sent to the drive section 47.48, so each solenoid 39.40 is driven in proportion to this function signal C, and both hydraulic clutches 34.36 connects in a sliding state. Therefore, the hydraulic clutch 34.3 of the high-low speed switching device 30
6 is connected while sliding, which acts as a load on the engine 2 and assists the braking force of the brake 25. At the same time, since the high/low speed switching device 30 is connected to the front wheels 10, the front wheels 10 are braked. In other words, the high/low speed switching device 30 assists the braking force, and four-wheel braking is performed, which brakes the front wheels 10 and the rear wheels 14, so that the vehicle can be reliably stopped within a short braking distance. Also, since the pressure of the hydraulic clutch 34, 36 is proportional to the traveling speed,
Braking distance can be kept constant regardless of speed.

If the traveling speed is medium speed, the speed discriminator 42 outputs a medium speed signal, so the low speed hydraulic clutch 34 is connected in a slipping state by the pressure proportional to the function signal C, and the brake 25 brakes the four wheels. .

Further, at low speeds, only the rear wheels 14 are braked by the brake 25.

In addition, in the embodiment, the high-low speed switching device 3 of the front wheel drive system 27
0 has been described, but it may be implemented in the transmission 2, and it is not limited to four-wheel drive, but may be two-wheel drive.

(Effects of the Invention) According to the present invention, the traveling power transmission system 19 includes two sets of transmission parts 35 and 40 having different transmission ratios in parallel, and
In a vehicle equipped with a friction-type hydraulic clutch 34.36 that selects between these two sets of transmission parts 35.40 and a brake 25 that brakes the drive wheels 14, both clutches 34.36 slip when the brake 25 is activated. Since the control means 50 is provided for connecting the brake 25 in the same state, when the brake 25 is activated, a braking force is generated between the two sets of transmission parts 34 and 36 having different transmission ratios, and this assists the braking force of the brake 25. can do. Furthermore, since the transmission parts 35 and 40 of the traveling power transmission system 19 are used, there is no need to increase the size of the brake 25, and the manufacturing cost does not increase.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which Fig. 1 is a configuration diagram of a power transmission system, Fig. 2 is a block diagram of a solenoid valve control circuit, Fig. 3 is a side view of the tractor, and Fig. 4 is a plan view thereof. It is. 14...-Rear wheel (drive wheel), 19-Traveling power transmission system,
34-low speed hydraulic clutch, 35-low speed transmission section, 36-high speed hydraulic clutch, 40-high speed transmission section, 42-.-speed detector, 44-brake switch, 45--speed discriminator, 46-.- Function generator, 50--control means.

Claims (1)

[Claims] (1) The traveling power transmission system 19 includes two sets of transmission parts 35, 40 with different transmission ratios in parallel, and a friction type hydraulic clutch 3 that selects these two sets of transmission parts 35, 40.
4, 36, and a brake 25 for braking the drive wheels 14, a control means 5 for connecting both the clutches 34, 36 in a slipping state when the brake 25 is activated.
A braking device for a vehicle, characterized in that it is equipped with a 0.