JPH0341969Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an auxiliary brake device for an industrial vehicle equipped with a hydraulic pump, such as a hydraulic truck crane.

(Prior art) In general, in industrial vehicles such as large trucks, in order to improve braking performance while driving, a main brake such as a hydraulic brake that has a direct braking function on the wheels and a main brake such as a hydraulic brake that has a direct braking function on the wheels and a brake that uses the inertia of the vehicle are used. It is also equipped with an auxiliary brake (retarder) that absorbs energy and assists the braking performance of the main brake.

As this auxiliary brake, for example, an engine brake that utilizes the pumping action of the engine, and an exhaust brake that further enhances the engine braking effect by increasing the exhaust resistance of the engine are widely known.

Incidentally, in recent years, there has been a trend in engines for industrial vehicles to increase engine output without increasing engine displacement through supercharging. If the load is the same), in the case of a supercharged engine, it is possible to use an engine with a smaller displacement than in the case of a non-supercharged engine.

However, the reduction in engine displacement that accompanies supercharging leads to a decrease in the pumping force of the engine, which in turn leads to a decrease in the performance of the engine brake or exhaust brake, and for this reason, it is difficult to ensure safe vehicle operation in large trucks, etc. In order to ensure this, it was desired to be equipped with an auxiliary brake that could compensate for the decline in performance of the engine brake or exhaust brake.

(Purpose of the invention) The present invention has been made in response to the above-mentioned demands, and is particularly designed to be equipped with a hydraulic pump that supplies hydraulic oil for a hydraulic actuator, such as a hydraulic truck crane, and to be used in a vehicle running engine. In an industrial vehicle driven by
By allowing the hydraulic pump to function as an auxiliary brake for the vehicle as necessary when braking the vehicle while the vehicle is running (that is, when the hydraulic pump does not need to be operated), it is possible to avoid any particular cost increase and to avoid braking. The purpose is to improve the braking performance of the vehicle without increasing the output loss of the engine during operation.

(Means for Achieving the Object) As a means for achieving the above object, the present invention uses a vehicle running engine as a power source for hydraulic work equipment such as a crane device mounted on a vehicle. In an industrial vehicle equipped with a driven hydraulic pump, the operation of each hydraulic pump is controlled by connecting and connecting the engine and each hydraulic pump with a clutch device, braking operation while the vehicle is running. The clutch device is connected at times as necessary so that each of the hydraulic pumps can be driven by the inertia of the vehicle.

(Function) According to the above-mentioned means, the present invention reduces the inertia of the vehicle by connecting the idle hydraulic pump to the engine in response to the depression of the brake pedal while the vehicle is running. part is absorbed as the driving force of the hydraulic pump (that is, the hydraulic pump functions as an auxiliary brake), and the braking performance of the vehicle is improved compared to the case where the hydraulic pump does not function as an auxiliary brake. .

(Embodiment) Hereinafter, a preferred embodiment of the present invention will be described with reference to FIGS. 1 and 2.

(Structure) FIG. 1 shows the main parts of the hydraulic circuit of a hydraulic truck crane, and FIG. 2 shows its control electric circuit. The vehicle portion of this truck crane is equipped with a main brake such as a hydraulic brake as a braking device and an exhaust brake as an auxiliary brake (not shown).

In the hydraulic circuit diagram of FIG. 1, reference numeral 1 is an engine, and 2, 3, and 4 are hydraulic pumps for supplying hydraulic oil to each hydraulic actuator (not shown) of a crane device (not shown), respectively. The hydraulic pumps 2, 3, 4 are connected to the engine 1 via a clutch device (electromagnetic clutch) 5 and are driven by the engine 1.

The pressure oil discharged from each of the hydraulic pumps 2, 3, and 4 is supplied to the main hydraulic circuit of the crane device via supply oil lines 21, 31, and 41 connected to each of the hydraulic pumps 2, 3, and 4, respectively. The oil tank 10 is further connected to the oil tank 10 via the return oil path 11 from the main hydraulic circuit.
It is refluxed to the side.

In the middle of the passage of the three supply oil passages 21, 31, 41, the respective supply oil passages 21, 31, 41
Electromagnetic switching valves 22, 32, and 42 are respectively provided to control opening and closing. In addition, each electromagnetic switching valve 2
2, 32, 42 are solenoid coils 2, respectively.
3, 33, and 43.

Further, each of the hydraulic pumps 2, 3, 4 of each of the supply oil passages 21, 31, 41 and each of the electromagnetic switching valves 2
Branch oil passages 25, 35, and 45 each having check valves 26, 36, and 46 are connected to intermediate positions between oil passages 2, 32, and 42, respectively. Each of these branch oil passages 25, 35, 45 is connected to each check valve 26, 3.
6 and 46, and are connected to the oil tank 10. Further, a relief valve 7 and an oil cooler 8 are connected in series in the oil passage between the confluence of the branch oil passages 25, 35, and 45 and the oil tank 10, and the relief valve 7 is connected in series with the oil cooler 8. A manual flow control valve 6 is connected in parallel. The flow rate control valve 6 is a two-position switching valve having a first position 6A with a variable throttle mechanism and a second position 6B with a passage closing mechanism. In addition, in the vicinity of this flow rate control valve 6,
An indicator lamp switch 15 is provided which detects when the flow rate control valve 6 is set to the second position and turns on an indicator lamp (not shown).
In addition, in FIG. 1, the reference numeral 9 is an oil filter.

In the electrical circuit shown in FIG. 2, reference numeral 50 is a clutch select switch that is turned on by the operator when performing crane work, that is, when it is necessary to connect the clutch device 5 and drive the hydraulic pumps 2, 3, and 4. 60 is an exhaust brake switch that is turned on when the exhaust brake (not shown) needs to be activated (that is, when the driver depresses the brake pedal). The clutch select switch 50 and the exhaust brake switch 60 are connected in parallel to the battery 19, and the clutch select switch 50 and the exhaust brake switch 60 are connected to a pair of switches facing in opposite directions. A solenoid coil 51 for switching the clutch device 5 (clutch solenoid coil) is connected in series via diodes 17 and 18. Therefore, the clutch solenoid coil 51 is immediately energized to connect the clutch device 5 when either the clutch select switch 50 or the exhaust brake switch 60 is turned on.
It acts to drive each hydraulic pump 2, 3, 4.

Also, at an intermediate position between the exhaust brake switch 60 and the diode 17 on the side of the exhaust brake switch 60, there is an exhaust valve that controls the operation of the air actuator for operating the exhaust brake (that is, the opening/closing operation of the exhaust passage of the engine 1). A brake solenoid coil 61 and switching valve solenoids 23, 33, and 43 that control the operation of the electromagnetic switching valves 22, 32, and 42 (see FIG. 1) are connected in parallel. Therefore, when the exhaust brake switch 60 is turned on, the exhaust brake solenoid coil 61 is energized and the exhaust brake action is started, and at the same time, each switching valve solenoid 23, 33, 4 is activated.
3 are respectively excited and the respective supply oil passages 21, 31,
41 (see Figure 1) is occluded.

(Operation and its effects) Next, the operation and its effects of this truck crane will be explained.

(a) During crane work During crane work, with the vehicle stopped, first manually set the flow control valve 6 to the second position 6B to enable the operation of the relief valve 7, and then turn the clutch select switch. 50 to excite the clutch solenoid coil 51, connect the clutch device 5, and drive each hydraulic pump 2, 3, 4. In this state,
Since the exhaust brake switch 60 is open, the switching valve solenoids 23, 33, 43 are de-energized, and the supply oil passages 21, 31, 41 are opened by the electromagnetic switching valves 22, 32, 42. , and each branch oil passage 25, 35, 45 is connected to the oil tank 10 side via a relief valve 7. Therefore, the pressure oil discharged from each hydraulic pump 2, 3, 4 is supplied to the main hydraulic circuit of the crane device via each supply oil path 21, 31, 41, and operates various hydraulic actuators to perform a predetermined work. to be carried out.
Note that during this crane work, the indicator lamp switch 15 is turned on, and the lighting of the indicator lamp (not shown) allows the operator to work with the crane (i.e., the pressure on each branch oil path 25, 35, 45 side is It can be easily verified that oil leakage is stopped.

(b) When the vehicle is running When the vehicle is running, the clutch select switch 50
Since the clutch device 5 is held open, the clutch device 5 is connected only when the exhaust brake switch 60 is turned on. Furthermore, when the exhaust brake switch 60 is turned on, the exhaust brake solenoid coil 61 and the three switching valve solenoids 23, 33, and 43 are both energized, and the exhaust brake air actuator (not shown) is activated. , each supply oil passage 21, 3 by each electromagnetic switching valve 22, 32, 42
1,41 is closed. Furthermore, the flow control valve 6 is set to the first position 6A by the operator, and the branch oil passages 25, 35, and 45 are opened.

Therefore, when the driver depresses the brake pedal while the vehicle is running, the hydraulic brake (main brake) is activated, and at the same time, the exhaust brake is activated by turning on the exhaust brake switch 60. Also, at this time, the clutch device 5 is activated at the same time as the exhaust brake is activated.
are connected and each hydraulic pump 2, 3, 4 is driven by the inertia of the vehicle, and each hydraulic pump 2, 3,
The oil discharged from 4 is recirculated to the oil tank 10 side while being throttled through a flow rate control valve 6.
The inertial force of the vehicle is reduced by the power consumed to drive each hydraulic pump 2, 3, 4, and the braking load on the main brake is reduced accordingly (that is, each hydraulic pump 2, 3, 4 acts as an auxiliary brake). ).

Therefore, when the hydraulic pumps 2, 3, and 4 function as auxiliary brakes in this way, the sum of the braking force exerted by each of the hydraulic pumps 2, 3, and 4 and the exhaust braking force is applied to the vehicle. acts as a total auxiliary braking force, the braking performance for the vehicle is improved by dividing the braking force by each of the hydraulic pumps 2, 3, and 4, compared to, for example, a conventional case where only the exhaust brake is used as an auxiliary brake. It will improve. That is, as mentioned above, even if the exhaust braking capacity decreases due to engine supercharging, the decrease is compensated for by the braking action of the hydraulic pumps 2, 3, and 4, so that the engine can reduce the exhaust gas by supercharging. Even when quantified, the braking performance of the vehicle is maintained at the same level as with a non-supercharged engine,
Safe driving of the vehicle is guaranteed.

The braking force exerted by each of the hydraulic pumps 2, 3, and 4 can be adjusted steplessly by adjusting the throttle of the flow rate control valve 6.

FIG. 3 shows an electrical circuit diagram of a truck crane equipped with an auxiliary brake device according to another embodiment of the present invention. This electrical circuit diagram is the same as the second one above.
Although the basic configuration is almost the same as the electrical circuit diagram in the figure,
The only difference from the above embodiment is that a select switch 62 is provided between each of the diodes 17, 18 and the clutch solenoid coil 51. Providing the select switch 62 in this way allows the driver to arbitrarily select the auxiliary braking force depending on the driving condition of the vehicle. That is,
In the case of the above embodiment (in the case of the electric circuit diagram shown in FIG. 2), when the exhaust brake is activated, the braking force from the hydraulic pumps 2, 3, and 4 always acts in conjunction with the exhaust brake (i.e., the auxiliary However, if a select switch 62 is provided as shown in the electrical circuit diagram of FIG. , 4 can be applied at the same time, or only the exhaust brake can be applied (that is, the auxiliary braking force is set in two stages). Therefore, the braking force for the entire vehicle can be set in two levels depending on various conditions such as road conditions, and control performance that is adapted to the actual driving conditions can be obtained, further improving the drivability of the vehicle. Become.

Although the above embodiment has been explained using a hydraulic truck crane as an example, the auxiliary brake device of the present invention is not limited to being applied to such a hydraulic truck crane, but can also be applied to a vehicle. It goes without saying that the present invention can be applied to any vehicle (for example, a hydraulic aerial work vehicle, etc.) equipped with a hydraulic pump that is in an idle state while traveling.

(Effects of the invention) The auxiliary brake device in an industrial vehicle equipped with the hydraulic pump of the present invention is driven by the vehicle running engine as a power source for hydraulic work equipment such as a crane device mounted on the vehicle. In an industrial vehicle equipped with a hydraulic pump, the operation of each hydraulic pump is controlled by connecting and connecting the engine and each hydraulic pump with a clutch device, when braking is performed while the vehicle is running. The present invention is characterized in that the clutch device is connected as necessary so that each of the hydraulic pumps can be driven by the inertia of the vehicle.

Therefore, according to the auxiliary brake device for an industrial vehicle equipped with a hydraulic pump according to the present invention, (1) the inertial force of the vehicle is absorbed as the driving force of the hydraulic pump (in other words, the hydraulic pump acts as an auxiliary brake). (2) Hydraulic pressure is maintained in an idle state when the vehicle is running. Since the pump functions as an auxiliary brake device, it is possible to easily improve vehicle control performance without increasing costs. Since it will not be driven if it is not activated, the hydraulic pump will not be driven unnecessarily and the engine output will not be wasted. Compared to the case where the engine is running, there is less loss of engine output when the vehicle is running, and the vehicle can run more efficiently.

[Brief explanation of the drawing]

Fig. 1 is a hydraulic circuit diagram of a main part of a hydraulic truck crane equipped with an auxiliary brake device according to an embodiment of the present invention, and Fig. 2 is an electric circuit diagram for controlling the auxiliary brake device of the truck crane shown in Fig. 1. , FIG. 3 is an electrical circuit diagram of an auxiliary brake device according to another embodiment of the present invention. 1... Engine, 2, 3, 4... Hydraulic pump,
5...Clutch device, 6...Flow control valve, 7...
Relief valve, 21, 31, 41... Supply oil path, 2
2, 32, 42...Solenoid switching valve, 25, 35, 4
5... Branch oil path, 23, 33, 43, 51, 61
... Solenoid coil, 50 ... Clutch select switch, 60 ... Exhaust brake switch, 6
2...Select switch.

Claims (1)

[Scope of utility model registration request] Engine 1 for running the vehicle as a power source for hydraulic work equipment such as a crane device mounted on the vehicle
The engine 1 and each hydraulic pump 2, 3, 4 are connected to each other by a clutch device 5, so that each hydraulic pump 2, 3, 4 is driven by a clutch device 5. In an industrial vehicle whose operation is controlled, the clutch device 5 is connected as necessary during a braking operation while the vehicle is running, and the hydraulic pumps 2, 3, and 4 are driven by the inertia of the vehicle. An auxiliary brake device for an industrial vehicle equipped with a hydraulic pump, characterized in that the auxiliary brake device is configured to be able to