JP2009280040A - Continuously variable transmission and irregular ground traveling vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a continuously variable transmission capable of suppressing deterioration with age in HMT and a waste of fuel and performing starting time swash plate inclination angle control without using a clutch electronic control mechanism. <P>SOLUTION: The continuously variable transmission is provided with: a hydro-mechanical transmission (HMT) 15 for performing continuously variable speed-change by a mechanical type transmission (MT) 13 arranged close to an engine output shaft 11a of a motive power transmission route reaching from an engine 11 to a drive wheel 12 and a static hydraulic type transmission (HST) 14 provided on the MT 13 in parallel and utilizing static pressure energy of a fluid; and an automatic centrifugal clutch mechanism 16 arranged on an engine output shaft 11a between the engine 11 and the HMT 15. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a continuously variable transmission for a vehicle, and in particular, a continuously variable transmission in which a mechanical transmission is interposed between an input shaft and an output shaft, and a hydrostatic transmission is provided in parallel with the mechanical transmission. And an irregular terrain vehicle.

  Conventionally, various vehicles such as large vehicles such as buses and trucks, vehicles for various construction machines, vehicles for various agricultural machines such as tractors, and leisure / sport industrial vehicles such as rough terrain vehicles (ATV) such as four-wheel buggy vehicles. A mechanical transmission (hereinafter referred to as “MT”) is interposed between an input shaft and an output shaft, and a hydrostatic pressure type using the MT and the hydrostatic energy of the fluid. A hydro mechanical transmission (hereinafter referred to as “HMT”), which is configured to perform a stepless speed change by combining a transmission (Hydro Static Transmission; hereinafter referred to as “HST”) via a planetary gear mechanism or the like. " Is well known.

  In addition, as an HMT as such a continuously variable transmission, for example, as shown in FIG. 5, a clutch mechanism 3 and a planetary gear mechanism 4 are configured in a power transmission path from the engine 1 to the drive wheels 2. MT5 and HST8 connected in parallel with a hydraulic pump 6 having a swash plate 6a connected to the engine 1 side and a hydraulic motor 7 having a swash plate 7a connected to the drive wheel 2 side are arranged in parallel. The one that constitutes the HMT 9 is known (for example, see Patent Document 1).

Further, as shown in FIG. 6, a brake switch 10 is interposed on the input side of the drive wheel 2 to electrically release the clutch according to the amount of depression of a brake pedal (not shown) and to neutralize the gear ratio while the vehicle is stopped. The structure to control is also known (for example, refer patent document 2).
Japanese Patent Laid-Open No. 11-236969 JP 2000-127780 A

  However, in the continuously variable transmission configured as described above, for example, in the technique disclosed in Patent Document 1, since the HMT 9 always continues to operate even during idling, the aging of the HMT 9 is accelerated. In addition to this, there has been a problem of wasteful use of fuel.

  Further, in the technique disclosed in Patent Document 2, since the clutch is disengaged and the gear ratio is neutralized while the vehicle is stopped, it is impossible to stand by at the inclination angle of the swash plate at the time of start, and sudden start is impossible. There was a problem.

  Therefore, in consideration of the above circumstances, the present invention can suppress the aging deterioration of the HMT and the wasteful use of fuel, and can perform the swash plate inclination angle control at the time of start without using the clutch electronic control mechanism. An object is to provide a step transmission.

  A continuously variable transmission according to the present invention includes a mechanical transmission disposed near an engine output shaft of a power transmission path from an engine to a drive wheel, and a hydraulic pressure which is provided side by side with the mechanical transmission and on the output shaft side of the engine. In a continuously variable transmission equipped with a hydromechanical transmission that performs a stepless shift by a hydrostatic transmission that uses static pressure energy of a fluid that is connected to a pump and an input shaft side of the driving wheel, respectively, An automatic centrifugal clutch mechanism is disposed on the engine output shaft between the engine and the hydromechanical transmission.

  Further, a running state detecting means for detecting the presence or absence of a running state of the vehicle, an engine speed detecting means for detecting the engine speed of the engine, and an HMT input rotation for detecting the input speed and the output speed of the hydromechanical transmission. Number detection means and HMT output rotation speed detection means, swash plate inclination angle detection means for detecting the swash plate inclination angle of the hydraulic pump, and each of the detected by the HMT input rotation speed detection means and the HMT output rotation speed detection means A calculating means for calculating a swash plate inclination angle after calculating a gear ratio based on a rotational speed; a swash plate inclination angle detected by the swash plate inclination angle detecting means when the automatic centrifugal clutch mechanism is in a disconnected state; and And a starting swash plate inclination angle correcting means for correcting the starting swash plate inclination angle by comparing with the swash plate inclination angle calculated by the calculating means. And butterflies.

  And a storage means for storing the swash plate inclination angle detected by the swash plate inclination angle detection means and the swash plate inclination angle calculated by the calculation means in association with a correlation curve, and the starting swash plate inclination angle The correcting means corrects the inclination angle of the swash plate at the start in association with the correlation curve stored in the storage means.

  Further, the continuously variable transmission according to any one of claims 1 to 3 is mounted on the rough terrain vehicle of the present invention.

  The continuously variable transmission of the present invention can suppress the aging deterioration of the HMT and the wasteful use of fuel, and can perform the swash plate inclination angle control at the time of starting without using the clutch electronic control mechanism.

  Next, a continuously variable transmission according to an embodiment of the present invention will be described with reference to the drawings, which is applied to an uneven terrain vehicle (ATV) such as a four-wheel buggy.

  FIG. 1 is a schematic diagram of a vehicle equipped with a continuously variable transmission according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of a continuously variable transmission according to an embodiment of the present invention, and FIG. 3 is an embodiment of the present invention. FIG. 4 is a graph showing the correlation between the transmission gear ratio and the swash plate angle.

  As shown in FIG. 1, a continuously variable transmission according to an embodiment of the present invention is disposed near an engine output shaft 11a in a power transmission path from an engine 11 to drive wheels (rear wheels in the present embodiment) 12. A mechanical transmission (hereinafter simply referred to as “MT”) 13, and a hydrostatic transmission (hereinafter simply referred to as “HST”) 14 that is provided in parallel with MT 13 and uses the static pressure energy of the fluid; A hydromechanical transmission (hereinafter simply referred to as “HMT”) 15 that performs a stepless speed change, and an automatic centrifugal clutch mechanism 16 disposed on the engine output shaft 11a between the engine 11 and the HMT 15. Yes.

  The MT 13 includes a gear 17 connected to the engine output shaft 11a via an automatic centrifugal clutch mechanism 16, and a planetary gear mechanism 18 connected to the drive wheel input shaft 12a and meshing with the gear 17.

  The HST 14 includes a hydraulic pump 19 having a swash plate 19a connected to the engine output shaft 11a, a hydraulic motor 20 having a swash plate 20a connected to the drive wheel input shaft 12a, and the hydraulic pump 19 And a hydraulic mechanism 21 that uses the static pressure energy of the fluid connected to the hydraulic motor 20.

  The automatic centrifugal clutch mechanism 16 is disposed in the middle of the engine output shaft 11a and separates the engine output shaft 11a into an input side and an output side, and the engine 11 is driven to rotate the engine output shaft 11a. When the engine output shaft 11a is connected, the input side and the output side of the engine output shaft 11a are connected, and when the engine output shaft 11a is not rotating, the input side and the output side of the engine output shaft 11a are disconnected.

  At this time, the automatic centrifugal clutch mechanism 16 is disconnected so as not to transmit to the output side the rotation of the engine output shaft 11a, which is not in the vehicle running state even when the engine 11 is driven, that is, the so-called idling speed slower than that during idling. Has been. Therefore, the automatic centrifugal clutch mechanism 16 can be reduced in size, and at the same time, the rotation of the engine output shaft 11a at the time of idling is not transmitted to the MT 13, so that the HMT 15 can be operated without electrical control of an electromagnetic clutch or the like. Mechanical aging and fuel consumption waste can be suppressed.

  On the other hand, the engine speed of the engine 11 is output to the control circuit 22. In addition to the throttle signal from the throttle position sensor 23, the control circuit 22 receives the input rotation speed and output rotation speed of the HMT 15, the inclination angle of the swash plate 19a of the hydraulic pump 19, and the like. . Furthermore, the control circuit 22 executes various controls related to vehicle travel based on a control program stored in the ROM 24. The ROM 24 also stores a startup swash plate inclination angle correction program according to the present invention, and constitutes a microcomputer with a control circuit 22 that executes the startup swash plate inclination angle correction program.

  Thereby, the control circuit 22 detects the presence or absence of the vehicle running state based on the throttle signal from the throttle position sensor 23 and the engine speed. Further, the control circuit 22 calculates a gear ratio based on the HMT input rotation speed and the HMT output rotation speed, and stores the gear ratio in the memory 25. Further, the control circuit 22 calculates the inclination angle of the swash plate 19 a based on the gear ratio stored in the memory 25. Further, the control circuit 22 compares the detected inclination angle of the swash plate 19a with the calculated inclination angle of the swash plate 19a to correct the starting swash plate inclination angle, and feeds back the correction result to the memory 25 (learning). To do.

The control circuit 22 is, for example,
(1) Throttle position sensor 23 = fully closed (2) HMT output speed = 0
(3) Engine rotational speed ≠ HMT input rotational speed (4) Engine rotational speed≈When any or any combination of idling rotational speeds is established, control to the swash plate angle required at the time of start is executed.

  As a result, the target speed ratio is calculated by the control circuit 22 and the swash plate angle is controlled by a motor or the like (not shown) by presetting the target engine speed according to the throttle opening and the vehicle speed. it can. At this time, the control circuit 22 causes an error in the relationship between the gear ratio actually required and the corresponding swash plate angle depending on environmental conditions (in-mechanism temperature, outside air temperature, etc.). There is a risk that feedback (learning) becomes ineffective and an error occurs in the swash plate angle and the start swash plate angle at the time of start.

  Therefore, the control circuit 22 learns the swash plate angles at a plurality of arbitrary speed ratios when the automatic centrifugal clutch mechanism 16 is connected and in a power transmission state, that is, the engine speed and the HMT input speed are the same. And stored in the memory 25.

  Next, an example of the starting swash plate inclination angle correction routine by the control circuit 22 will be described with reference to the flowchart of FIG.

(Step S1)
In step S1, the control circuit 22 determines whether or not the automatic centrifugal clutch 16 is in a disengaged state, that is, whether the vehicle is in a traveling state. When the automatic centrifugal clutch 16 is in a traveling state, the control circuit 22 proceeds to step S2. Step S1 is monitored.

  Note that the control circuit 22 is a mechanism for mechanically connecting / disconnecting the input side and the output side of the engine output shaft 11a, so that the automatic centrifugal clutch 16 is in a connected state. Judgment is based on the vehicle running state. Therefore, in the present embodiment, the control circuit 22 determines that the vehicle is in a traveling state when the throttle position sensor 23 is not fully closed and the engine speed is equal to the HMT input speed.

(Step S2)
In step S2, the control circuit 22 obtains the actual swash plate inclination angle of the swash plate 19a by using a detection sensor (not shown) for detecting the angle of the swash plate 19a, as well as the HMT input rotational speed and the HMT. After calculating the gear ratio based on the output rotational speed, the tilt angle of the swash plate 19a is calculated using the calculated gear ratio, and the calculated swash plate tilt angle is subtracted from the actual swash plate tilt angle ( If (absolute value) is "0 (zero)", the process proceeds to step S3, and the value (absolute value) obtained by subtracting the swash plate inclination angle calculated from the actual swash plate inclination angle is not "0 (zero)". In this case, the process proceeds to step S4.

(Step S3)
In step S3, for example, as shown in the graph shown in FIG. 4, the control circuit 22 correlates when the swash plate inclination angle calculated in step 2 is different from the correlation curve between the transmission ratio and the swash plate angle. The curve is corrected to the calculated inclination angle, the corrected correlation curve is stored in the ROM 24, and the process proceeds to step S5.

(Step S4)
In step S4, the control circuit 22 stores in the memory 25 the gear ratio associated with the actual swash plate inclination angle in step S2 and the calculated swash plate inclination angle, and calculates the actual swash plate inclination angle and the calculated swash plate inclination. Feedback control is executed so that the angles match, and the process loops to step S1.

(Step S5)
In step S5, the control circuit 22 corrects the starting swash plate angle based on the correlation curve corrected in step S3, and ends this routine.

  At this time, the control circuit 22 can determine the starting swash plate angle based on the correlation curve corrected in response to a change in environmental conditions in the vehicle running state immediately before the vehicle stop state.

  Moreover, since the control circuit 22 can determine the optimum starting swash plate angle when the automatic centrifugal clutch 16 is in the disconnected state, and can control the angle of the swash plate 19a to the starting swash plate angle. Excellent acceleration at start-up, especially in rough terrain vehicles, etc., which can realize smooth start acceleration that is imaged by the driver and improve operability during rough terrain where vehicle control is difficult Can do.

1 is a schematic diagram of a vehicle equipped with a continuously variable transmission according to an embodiment of the present invention. Explanatory drawing of the continuously variable transmission which concerns on one Embodiment of this invention, The flowchart of the control routine by the control circuit in the continuously variable transmission which concerns on one Embodiment of this invention, It is a graph of the correlation between the transmission gear ratio and the swash plate angle in the continuously variable transmission according to an embodiment of the present invention. It is a schematic diagram of the vehicle carrying the conventional continuously variable transmission. It is a schematic diagram of the vehicle carrying the other continuously variable transmission which concerns on the past.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Engine 12 ... Drive wheel 11a ... Engine output shaft 13 ... Mechanical transmission (MT)
14 ... Hydrostatic transmission (HST)
15 ... Hydromechanical transmission (HMT)
16 ... Clutch mechanism (centrifugal clutch mechanism)
DESCRIPTION OF SYMBOLS 18 ... Planetary gear mechanism 19 ... Hydraulic pump 19a ... Swash plate 20 ... Hydraulic motor 20a ... Swash plate 21 ... Hydraulic mechanism 22 ... Control circuit 24 ... ROM
25 ... Memory

Claims (4)

A mechanical transmission arranged near the engine output shaft of the power transmission path from the engine to the drive wheels, and a hydraulic pump and an input shaft side of the drive wheels arranged in parallel with the mechanical transmission and on the output shaft side of the engine In a continuously variable transmission equipped with a hydromechanical transmission that uses a hydrostatic transmission that utilizes the hydrostatic energy of a fluid connected to each of the hydraulic motors and a continuously variable transmission,
A continuously variable transmission, wherein an automatic centrifugal clutch mechanism is disposed on the engine output shaft between the engine and the hydromechanical transmission.   Traveling state detecting means for detecting the presence or absence of a vehicle traveling state, engine rotational speed detecting means for detecting the engine rotational speed of the engine, and HMT input rotational speed detection for detecting the input rotational speed and the output rotational speed of the hydromechanical transmission , A swash plate inclination angle detection means for detecting a swash plate inclination angle of the hydraulic pump, and each rotation speed detected by the HMT input rotation speed detection means and the HMT output rotation speed detection means. Calculating means for calculating the gear ratio after calculating the transmission ratio, and the swash plate inclination angle detected by the swash plate inclination angle detecting means when the automatic centrifugal clutch mechanism is in a disconnected state, and the calculating means. A starting swash plate inclination angle correcting means for correcting the starting swash plate inclination angle by comparing with the swash plate inclination angle calculated in Continuously variable transmission according to claim 1 that. Storage means for storing the swash plate inclination angle detected by the swash plate inclination angle detection means and the swash plate inclination angle calculated by the calculation means in association with a correlation curve;
The continuously variable transmission according to claim 2, wherein the starting swash plate inclination angle correcting means corrects the starting swash plate inclination angle in association with the correlation curve stored in the storage means.   An uneven terrain vehicle equipped with the continuously variable transmission according to any one of claims 1 to 3.

Images