JP2000234663A - Hydromechanical transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an HMT which can realize a retarder system by a simple mechanism. SOLUTION: This HMT is provided with HST retarder means by a flow regulating valve 11 which selectively connects the high pressure side hydraulic line 4a, 4b and low pressure side hydraulic line 4b, 4a of an HST 200 in the inside of the HMT and also is controlled its operation by opening/closing control arranged in a controller 10, and braking force control means for obtaining required braking force by the combination of retarder means by the HST 200 and normal engine brake means with engine exhaust brake means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydromechanical transmission (hereinafter, referred to as "HMT"), which is a continuously variable transmission used for buses, trucks, various construction machines, various industrial machines, and the like, and more particularly to such a transmission. ,
HMT with retarder system.

[0002]

2. Description of the Related Art In order to decelerate a vehicle safely and reduce wear of brakes, a retarder system is known that performs a deceleration action by absorbing the traveling energy of the vehicle other than the brake. Here, a “vehicle power recovery control method and a power regeneration control method, filed on June 3, 1998 by the same applicant as the present application:
In the HMT disclosed in "-154568 (hereinafter referred to as background art)", a hydraulic circuit that can be used as a retarder system is disclosed. Hereinafter, the configuration of the HMT and the retarder system disclosed in the background art will be described with reference to FIGS.

(Configuration of HMT) The engine 1 and the input rotation from the engine 1 are steplessly changed in speed to drive the left and right driving wheels 1.
An HMT is provided as a continuously variable transmission for transmitting to the 2 and 12 sides. The HMT includes a mechanical transmission (hereinafter, referred to as a “mechanism”) including a clutch mechanism connected to the input shaft 30 and a planetary gear mechanism connected to the output shaft 40.
Called MT. ) 100, a hydraulic pump 2 disposed on the engine 1 side and a hydraulic motor 3 disposed on the drive wheels 12 and 12 side are connected by a closed circuit 4 to a hydrostatic transmission (hereinafter referred to as HST).
200.

A swash plate type piston pump is used for the hydraulic pump 2 and the hydraulic motor 3, and the angle of the swash plate 2a of the hydraulic pump 2 can be changed between -17 ° and + 17 °. The angle of the swash plate 3a of the hydraulic motor 3 can be changed between -17 ° and + 17 °, similarly to the swash plate 2a of the hydraulic pump 2.

Power is transmitted between the MT 100 and the HST 200 on the engine 1 side by a gear 24 and a gear 25, and on the drive wheels 12, 12, power is transmitted by a gear 26 and a gear 27.

(Configuration of Power Recovery and Regeneration Apparatus) Next, the configuration of the power recovery and regeneration apparatus will be described.

[0007] First to third directional control valves 6, 7, which are operated and controlled by opening and closing control provided in a controller 10, are provided.
8 is provided. As the supply / discharge line, a first hydraulic line 4a and a second hydraulic line 4b constituting the closed circuit 4 of the HST 200, and the first hydraulic line 4a and the second hydraulic line 4b A pair of high-pressure selection lines 71 and 72 connected to each other via a stop valve 9a and a second check valve 9b; a downstream side of the first check valve 9a and the second check valve 9b; And a first supply / discharge line 73 connecting the first hydraulic line 4a and the second hydraulic line 4b to the accumulator 5, respectively.

[0008] First directional switching valve 6 and second directional switching valve 7
Are connected to each other, and the first directional control valve 6 and the second directional control valve 7 are connected to the pressure accumulator 5 by connecting the third directional control valve 8 to the middle of the first connection line 74. And a second supply / discharge line 75 to be connected. Further, a third supply / discharge line 76 that connects the third directional control valve 8 and the accumulator 5 is provided.

The first directional control valve 6 and the second directional control valve 7 are provided with a second connection line 77, which is connected to a reservoir tank 78. Second
A first hydraulic pressure sensor 80 is disposed on the supply / discharge line 75, a second hydraulic pressure sensor 81 is disposed on the third supply / discharge line 76,
A third hydraulic pressure sensor 82 is provided in the first supply / discharge line 73. The second supply / discharge line 75 has a flow control valve 1 for controlling the amount of hydraulic oil from the accumulator 5 to the closed circuit 4.
1 is provided.

The hydraulic pressure on the closed circuit 4 side of the HST 200 is detected by the first hydraulic pressure sensor 80 and the third hydraulic pressure sensor 82, while the hydraulic pressure on the accumulator 5 side is detected by the second hydraulic pressure sensor 8
1 and a determination section provided in the controller 10 determines whether or not the power can be recovered based on the detected values. The accumulator 5 has
A relief valve 13 is provided for maintaining the operating oil pressure in the accumulator 5 at a pressure equal to or lower than a certain value.

Signals from a first rotation speed detector 83 for detecting the rotation speed of the gear 25 and a second rotation speed detector 84 for detecting the rotation speed of the gear 26 are input to the controller 10. Is done. Signals from the accelerator detector 22 and the brake detector 23 are also input to the controller 10.

The first directional control valve 6 is of a four-port, three-position switching type, and is provided in the first hydraulic line 4a and connects the hydraulic pump 2 and the hydraulic motor 3 to the first switching position. (The middle position in the figure), a second switching position (upper position in the figure) connecting the hydraulic pump 2, the hydraulic motor 3 and the first connection line 74, and the hydraulic pump 2, the hydraulic motor 3 and the second Third switching position for connecting the connection line 77 (lower position in the figure)
In response to an operation command from the controller 10, the position can be switched to any of the above-mentioned positions by operating a solenoid or the like.

The second directional switching valve 7 is of a four-port, three-position switching type, and is provided on the second hydraulic line 4b and connects the hydraulic pump 2 and the hydraulic motor 3 to a first switching position. (The middle position in the figure), a second switching position (the lower position in the figure) connecting the hydraulic pump 2, the hydraulic motor 3 and the first connection line 74, and the hydraulic pump 2, the hydraulic motor 3 and the Third switching position for connecting two connection lines 77 (upper position in the figure)
In response to an operation command from the controller 10, the operation can be switched to any of the above positions by operating a solenoid or the like.

The third directional control valve 8 is of a three-port three-position switching type, and has a first switching position for shutting off the first supply / discharge line 73, the second supply / discharge line 75 and the third supply / discharge line 76. (Center position in the figure) and a second switching position (left position in the figure) connecting the first supply / discharge line 73 and the third supply / discharge line 76.
And a third switching position (the right side position in the figure) for connecting the second supply / discharge line 75 and the third supply / discharge line 76. It can be switched to any of the positions.

The hydraulic pump 2 in each mode of the power recovery (retarder) operation (at the time of deceleration) of the vehicle having the above configuration.
The angle control of the swash plate 2a and the swash plate 3a of the hydraulic motor 3 and the control of the engine speed (hereinafter referred to as the input speed) are performed according to each operation mode as shown in FIG. Transmission ratio, input rotation speed, swash plate angle (θm) (θ
p) "is controlled. This makes it possible to control the “recovered oil amount” and the “recovery power” as shown in FIG.

[0016]

However, in the HMT having the above-described structure, the main purpose is to regenerate and recover power, and the HMT can be used as a retarder system. , The system is too big.

That is, the HMT includes an HST as a hydrostatic transmission, and a power recovery mechanism and a retarder system are constructed by using the HST. However, a pressure accumulator and an oil cooler are required. Therefore, the cost and weight increase when used as a retarder system.

On the other hand, when the vehicle is braked solely by the HMT without using the retarder system during deceleration, it is possible to obtain a braking torque by the engine exhaust brake. However, as shown in FIG. 8, when the necessary deceleration is set to 0.10 G, in the high-speed region (the latter half of Mode 3 to the entire region of Mode 4), even if the engine exhaust brake is used together, It is not possible to obtain a proper deceleration. Also,
In the low speed region (the entire region of mode 1), the deceleration becomes too large even when the engine exhaust brake is not used.

Accordingly, an object of the present invention is to provide an HMT capable of realizing a retarder system capable of generating a sufficient and sufficient braking force over the entire speed change range with a simple mechanism.

[0020]

An HM according to the present invention is provided.
At T, the MT (100) and the HST (200) including a high-pressure relief circuit therein are arranged side by side in the power transmission path connecting the input shaft (30) and the output shaft (40), and the multi-speed range mode is set. A normal engine braking means, an engine exhaust braking means,
The high pressure side hydraulic line (4a, 4b) and the low pressure side hydraulic line (4b, 4a) of (200) are selectively connected to the flow control valve (1).
1) a retarder means for connecting in step 1), a braking force control means for obtaining a braking force by the engine brake means, the engine exhaust brake means, and the retarder means during braking in a high speed shift range mode. Have.

This makes it possible to obtain, by the retarder means, a braking force which was conventionally insufficient during braking in the high speed shift range mode. Further, it is possible to level the braking capacity within a predetermined value range.

Further, in order to carry out the above-mentioned invention in a more preferable state, the following second structure is adopted. The retarder means directly connects the low pressure side hydraulic line of the flow control valve (11) to an oil tank, and can be connected to and disconnected from the output shaft (40), and a charge pump (15). 15) HST (200)
And a refueling line connected to the charge port.

According to any of the above configurations, most of the existing HMT-specific devices can be used, so that an increase in weight and cost can be suppressed.

Further, by adopting the second configuration,
The oil cooler attached to the HMT can be effectively used, and the rise in oil temperature in the HST can be controlled.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an HMT retarder system according to the present invention will be described below with reference to FIGS. 1 and 2 are schematic configuration diagrams of the HMT according to the present embodiment, and FIG. 3 is a block diagram illustrating control of the retarder operation of the HMT according to the present embodiment.

FIG. 4 shows the HMT according to this embodiment.
"Control of pump swash plate angle", "Motor output shaft change", "ON / OFF control of engine exhaust brake", "Change of retarder power" in each mode during retarder operation
And "Vehicle braking force by retarder" is a diagram showing
FIG. 5 is a diagram illustrating the retarder capability of the HMT according to the present embodiment.

Since the basic configuration of the HMT is the same as that of the HMT described in the background art, parts having the same configuration as the background art are denoted by the same reference numerals, and detailed description thereof will be made. Is omitted.

(Configuration of Retarder System) The configuration of the retarder system according to the present embodiment will be described with reference to FIG. The high-pressure side hydraulic lines (4a, 4b) and the low-pressure side hydraulic lines (4b, 4a) of the HST (200) are selectively connected, and the flow rate thereof is controlled by opening and closing control provided in the controller 10. Flow control valve 1
One.

As the supply / discharge lines, a first hydraulic line 4a and a second hydraulic line 4b constituting the closed circuit 4 of the HST 200, and the first hydraulic line 4a and the second hydraulic line 4b A pair of first selection lines 71 and 72 connected to each other via a check valve 9a and a second check valve 9b.
And a first supply / discharge line 73 connecting the first hydraulic line 4 a and the second hydraulic line 4 b to the flow control valve 11.

Further, the first hydraulic line 4a and the second hydraulic line 4b constituting the closed circuit 4 of the HST 200, and the first hydraulic line 4a and the second hydraulic line 4b are respectively connected to a third check valve 10a. , A pair of second selection lines 74 and 75 connected to each other via the fourth check valve 10 b, and a second supply / discharge line 76 connecting the second selection lines 74 and 75 to the downstream side of the flow control valve 11. And

Here, the third check valve 10a and the fourth check valve 10b and the second selection lines 74 and 75 are elements included in the standard configuration of the HMT.

Signals from a first rotation speed detector 83 for detecting the rotation speed of the gear 25 and a second rotation speed detector 84 for detecting the rotation speed of the gear 26 are input to the controller 10. Is done. Signals from the accelerator detector 22 and the brake detector 23 are also input to the controller 10.

FIG. 2 shows a configuration in which a charge pump 15 which can be connected to and disconnected from the output shaft 40 is provided.

(Control of Retarder Operation) Next, control of the retarder operation of the HMT having the retarder system having the above configuration will be described with reference to FIG. First, based on information obtained from the "accelerator detector 22" and the "brake detector 23", the "deceleration request sensing means 300" determines whether deceleration is necessary. If deceleration is not required, the process proceeds to "normal operation control means 306".

On the other hand, if deceleration is necessary, the operation proceeds to the "operation state confirming means 301", and after confirming "vehicle speed", "gear ratio", "mode" and "swash plate angle" of HST, "H"
ST retarder control necessity determination means 302 "and" engine exhaust brake necessity determination means 303 "are simultaneously performed.

"HST retarder control necessity determination means 30"
In [2], if the HST retarder control is necessary, the process proceeds to “HST swash plate control amount determining means 304”, and
The swash plate control amount of the HST is determined, and the angle of the swash plate of the HST is controlled. If the HST retarder control is unnecessary, the process returns to the "deceleration request sensing means 300" to determine whether deceleration is necessary.

In the "engine exhaust brake necessity determining means 303", when the engine exhaust brake is necessary, the process proceeds to "exhaust pipe closing means 305" to control ON / OFF of the throttle of the exhaust pipe. . If the engine exhaust brake is unnecessary, the process returns to the "deceleration request sensing means 300" to determine whether deceleration is necessary.

Based on the control of the HMT retarder operation, as shown in FIG. 4, "swash plate angle (θm) (θp)", "motor output shaft acceleration", and "engine exhaust brake" ON / OFF ”is controlled. This makes it possible to obtain the “retarder power” and the “vehicle braking force by the retarder” shown in FIG.

As a result, as shown in FIG. 5, in mode 4 and part of mode 3, the engine exhaust brake + HST
Deceleration due to the engine exhaust brake alone in most of mode 3, deceleration due to engine exhaust brake + HST in part of mode 2, and deceleration due to engine exhaust brake alone in most of mode 2 and mode 1. An appropriate braking force can be obtained.

As described above, the HMT according to the present embodiment
In the retarder system of (1), the flow control valve 11 is provided between the high pressure side hydraulic line and the low pressure side hydraulic line of the HST. At the same time, the swash plate angles (θm) and (θp) are controlled in the direction in which the pump capacity of the HST increases, and hydraulic oil sufficient to obtain a required input rotation speed is supplied from the flow control valve 11 to the low-pressure side hydraulic line. Or drain to oil tank. This allows
The retarder effect as shown in FIG. 5 can be generated.

As a result, the braking ability in the highest speed range is 5
It is possible to increase from 0% to 100%,
It is possible to equalize the braking capacity within a predetermined value range.

In FIG. 5, the total deceleration exceeds the required deceleration even when the HST retarder effect is zero in the low speed range. However, since the HMT can basically control the gear ratio and the engine speed to control the braking force by the engine, it is also possible to control this part in accordance with the required deceleration.

Further, in the HMT retarder system according to the present embodiment, most of the equipment unique to the HMT can be used, so that the weight and the cost are slightly increased.

Further, since most of the braking energy is released into the air via the engine, an oil cooler is not required. Further, when a charge pump is additionally provided, it can be used as an emergency backup pump.

Although the above embodiment has been described with reference to a case where the present invention is applied to a four-mode machine, the present invention is not necessarily limited to this model. It is also possible to apply the same technical idea.

As described above, the embodiments disclosed herein are illustrative in all aspects and are not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and includes all modifications within the scope and meaning equivalent to the terms of the claims.

[0047]

According to the first and second aspects of the present invention, a flow rate control valve and its attached equipment are provided by utilizing a speed change function that does not cut off power transmission and a built-in HST function, which are inherently provided in the HMT. In some cases, adding only the charge pump to the HST makes it possible to obtain a uniform braking force in all speed ranges.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a first embodiment of an HMT according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a second embodiment of the HMT according to the embodiment of the present invention.

FIG. 3 is a block diagram illustrating control of the retarder operation of the HMT according to the present embodiment.

FIG. 4 shows “control of swash plate angle of pump”, “change of motor output shaft”, and “ON / O of engine exhaust brake” in each mode during retarder operation of the HMT in the present embodiment.
It is a figure which shows "FF control", "change of retarder power", and "vehicle braking force by retarder".

FIG. 5 is a diagram illustrating a retarder capability of the HMT in a case where the capability of the engine brake and the capability of the engine exhaust brake are not controlled in the present embodiment.

FIG. 6 is a schematic configuration diagram of an HMT in the background art.

FIG. 7 shows “gear ratio”, “input rotation speed”, “recovered oil amount”, “recovered power”, and “swash plate angle” in each mode during the power recovery operation (retarder operation) of the HMT in the background art. θm, θp) ”.

FIG. 8 is a diagram showing the deceleration ability of the HMT in the background art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Hydraulic pump 2a Swash plate 3 Hydraulic motor 3a Swash plate 4 Closed circuit 4a 1st hydraulic line 4b 2nd hydraulic line 9a 1st check valve 9b 2nd check valve 10a 3rd check valve 10b Fourth check valve 10 Controller 11 Flow control valve 12 Wheel 13 Relief valve 15 (Addition) Charge pump 22 Accelerator detector 23 Brake detector 24, 25, 26, 27 Gear 30 Input shaft 40 Output shaft 71, 72 First selection Line 73 First supply / discharge line 74, 75 Second selection line 76 Second supply / discharge line 83 First rotation speed detector 84 Second rotation speed detector 100 MT 200 HST

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) F02D 9/06 F02D 9/06 D 29/00 29/00 H 29/02 341 29/02 341 29/04 29/04 H F16H 61/40 F16H 61/40 F G F term (reference) 3D041 AA33 AA66 AB07 AC01 AC18 AC22 AC26 AD10 AD22 AD23 AD39 AD41 AD51 AE03 AE11 AE30 AE39 AE41 AE45 AF00 3D047 BB51 3G065 AA3 EA05 A09 DB15 EA11 EB03 EB07 EC04 3J053 AB14 AB17 AB48

Claims (2)

[Claims] A mechanical transmission (10) is provided in a power transmission path connecting an input shaft (30) and an output shaft (40).
0) and a hydro-mechanical transmission (200) including a high-pressure relief circuit therein and having a multi-speed range mode, comprising: a normal engine braking means, an engine exhaust braking means, Static transmission (20
Retarder means by selectively connecting the high-pressure side hydraulic lines (4a, 4b) and the low-pressure side hydraulic lines (4b, 4a) by a flow control valve (11), and braking in a high speed range mode A hydromechanical transmission, sometimes comprising braking force control means for obtaining a braking force by the engine braking means, the engine exhaust braking means, and the retarder means. 2. The low pressure side hydraulic line (4) of the flow control valve (11).
b, 4a) is connected directly to the oil tank and the output shaft (4
0) that can be connected to and disconnected from the charge pump (1)
5) The hydromechanical transmission according to claim 1, comprising: a refueling line connecting a discharge side of the charge pump (15) to a charge port of the hydrostatic transmission (200).