GB2395533A - Automatic transmission for vehicle with hydraulic motor. - Google Patents
Automatic transmission for vehicle with hydraulic motor. Download PDFInfo
- Publication number
- GB2395533A GB2395533A GB0227398A GB0227398A GB2395533A GB 2395533 A GB2395533 A GB 2395533A GB 0227398 A GB0227398 A GB 0227398A GB 0227398 A GB0227398 A GB 0227398A GB 2395533 A GB2395533 A GB 2395533A
- Authority
- GB
- United Kingdom
- Prior art keywords
- vehicle
- speed
- travelling
- travel
- transmission
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H61/02—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing characterised by the signals used
- F16H61/0202—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing characterised by the signals used the signals being electric
- F16H61/0204—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing characterised by the signals used the signals being electric for gearshift control, e.g. control functions for performing shifting or generation of shift signal
- F16H61/0206—Layout of electro-hydraulic control circuits, e.g. arrangement of valves
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H59/00—Control inputs to control units of change-speed-, or reversing-gearings for conveying rotary motion
- F16H59/68—Inputs being a function of gearing status
- F16H2059/6838—Sensing gearing status of hydrostatic transmissions
- F16H2059/6861—Sensing gearing status of hydrostatic transmissions the pressures, e.g. high, low or differential pressures
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H47/00—Combinations of mechanical gearing with fluid clutches or fluid gearing
- F16H47/02—Combinations of mechanical gearing with fluid clutches or fluid gearing the fluid gearing being of the volumetric type
- F16H47/04—Combinations of mechanical gearing with fluid clutches or fluid gearing the fluid gearing being of the volumetric type the mechanical gearing being of the type with members having orbital motion
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H59/00—Control inputs to control units of change-speed-, or reversing-gearings for conveying rotary motion
- F16H59/14—Inputs being a function of torque or torque demand
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H59/00—Control inputs to control units of change-speed-, or reversing-gearings for conveying rotary motion
- F16H59/14—Inputs being a function of torque or torque demand
- F16H59/26—Inputs being a function of torque or torque demand dependent on pressure
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H59/00—Control inputs to control units of change-speed-, or reversing-gearings for conveying rotary motion
- F16H59/36—Inputs being a function of speed
- F16H59/44—Inputs being a function of speed dependent on machine speed of the machine, e.g. the vehicle
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H59/00—Control inputs to control units of change-speed-, or reversing-gearings for conveying rotary motion
- F16H59/48—Inputs being a function of acceleration
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H61/02—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing characterised by the signals used
- F16H61/0202—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing characterised by the signals used the signals being electric
- F16H61/0204—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing characterised by the signals used the signals being electric for gearshift control, e.g. control functions for performing shifting or generation of shift signal
- F16H61/0213—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing characterised by the signals used the signals being electric for gearshift control, e.g. control functions for performing shifting or generation of shift signal characterised by the method for generating shift signals
Abstract
An engine 11 of a vehicle drives a pump 12 which in turn drives a hydraulic motor 13 which is connected to and drives a transmission 14. A separate pump 17 may be connected to the transmission 14 which detects the speed of the vehicle by being rotated in proportion to the rotation of the output shaft of the transmission 14. A gear change valve 16 may be provided which feeds pressurised oil to a transmission pump to select a first speed clutch 14F or a second speed clutch 14S dependent on a controller 30. When an accelerator pedal 23A is depressed a certain amount, the pressure from the pump 12 is above a certain value, and the vehicle is decelerating, for example, when the vehicle is travelling uphill, the controller 30 sends a shiftdown signal to change from second speed clutch 14S to first speed clutch 14F.
Description
AUTOMATIC TRANSMISSION APPARATUS OF
HYDRAULIC TKAVELLING VEHICLE
Technical Field
The present invention relates to an automatic transmission apparatus of a hydraulic travelling vehicle.
Background Art
A transmission, which is mounted on an industrial vehicle that is a working vehicle, needs to cover a speed range from a dead slow speed range for a primary operation to a normal travelling speed to travel on ordinary roads, and 15 therefore it generally has multiple speed gears for both forward and reverse travelling. An automatic transmission, which is capable of automatically selecting the optimal speed gear according to a driving state of such a vehicle, is proposed, and as travailing state detecting means, it adopts a vehicle 20 speed sensor which detects a travelling speed of the vehicle, an acceleration opening degree sensor which detects a depressing amount of an accelerator pedal, and the like (for example, Japanese Patent Laid-open No. 5-223149).
However, in a hydraulic travelling vehicle, it is 25 effective to change a speed gear of a transmission combined
with a hydraulic motor according to a change in load applied to a hydraulic pump and a hydraulic motor, and it is impossible to obtain an automatic transmission capable of automatically selecting an optimal speed gear according to the 5 driving state of the hydraulic travelling vehicle by using the art disclosed in Japanese Patent Laid-open No. 5- 223149.
Further, the above-described prior art has the problems of
being expensive, and of being trouble-prone due to a complicated structure to make its maintenance difficult.
Summary of the Invention
The present invention is made in view of the above-described problems, and has its object to provide an 15 automatic transmission apparatus of a hydraulic travelling vehicle capable of automatically selecting an optimal speed gear according to a driving state of the vehicle.
In order to attain the above-described object, a first aspect of an automatic transmission apparatus of a hydraulic 20 travelling vehicle according to the present invention includes: gear change control means of a transmission; load pressure detecting means for detecting load pressure of a travel pump for feeding pressure oil to a travel motor; vehicle speed detecting means for detecting vehicle speed of the hydraulic 25 travelling vehicle; and a controller which sends a shift-down
signal to the gear change control means to shift down the transmission, when the load pressure detected by the load pressure detecting means is a predetermined value or more, and it is determined that the hydraulic travelling vehicle is in 5 a decelerating state based on the vehicle speed detected by the vehicle speed detecting means.
According to the above constitution, when the load pressure of the travel pump is a predetermined value or more, and the hydraulic travelling vehicle is in the decelerating state, 10 the transmission is shifted down. As a result, in the hydraulic travailing vehicle being the working vehicle, the optimal speed gear is automatically selected according to the driving state of the vehicle, and it can comfortably travel even on the travel road with large travelling resistance, such as a 15 slope with an up grade, without drastically reducing the vehicle speed.
A second aspect of an automatic transmission apparatus of a hydraulic travelling vehicle according to the present invention includes: gear change control means of a 20 transmission; depressing amount detecting means for detecting a depressing amount of an accelerator pedal; load pressure detecting means for detecting load pressure of a travel pump for feeding pressure oil to a travel motor; vehicle speed detecting means for detecting vehicle speed of the hydraulic 25 travelling vehicle; and a controller which sends a shift-down
signal to the gear change control means to shift down the transmission, when the load pressure detected by the load pressure detecting means is a predetermined value or more, the depressing amount detected by the depressing amount 5 detecting means is a predetermined value or more, and it is determined that the hydraulic travelling vehicle is in a decelerating state based on the vehicle speed detected by the vehicle speed detecting means.
According to the above constitution, when the load 10 pressure of the travel pump is a predetermined value or more, the depressing amount of the accelerator pedal is a predetermined or more, and the hydraulic travelling vehicle is in the decelerating state, the transmission is shifted down.
As a result, in the hydraulic travelling vehicle being a working 15 vehicle, the optimal speed gear is automatically selected according to the driving state of the vehicle, and it can comfortably travel even on the travel road with large travelling resistance, such as a slope with an up grade, without drastically reducing the vehicle speed.
2() Further, in the automatic transmission apparatus of the hydraulic travelling vehicle, the gear change control means may be a two-position switching valve. According to the constitution, the gear change control means of the transmission is made a two-position switching valve with a simple structure 25 at low cost. As a result, the structure of the automatic
transmission apparatus of the hydraulic travelling vehicle is simplified, and therefore the production cost of the automatic transmission apparatus of the hydraulic travelling vehicle can be reduced.
5 In the automatic transmission apparatus of the hydraulic travelling vehicle, the transmission may be of two travel stages. According to the constitution, cost reduction is made possible. In addition, since the above-described load pressure detecting means is used, the performance at the same 10 level as the prior art or at the level having no problem in
practical use can be obtained in spite of inexpensive constitution such as a two-speed gear transmission and a two-position switching valve.
15 Brief Description of the Drawings
FIG. 1 is a system block diagram of an automatic transmission apparatus according to an embodiment of the present invention.
Best Mode for Carrying out the Invention
An embodiment according to an automatic transmission of a hydraulic travelling vehicle of the present invention will 25 be explained with reference to the drawing. FIG. 1 is a
system block diagram of an automatic transmission apparatus.
As shown in FIG. 1, a travel pump 12 is connected to an engine 11, and the travel pump 12 is driven by the engine 11 and discharges pressure oil. The pressure oil, which is 5 discharged from the travel pump 12, is fed to travel motor 13 via a travel control valve 21 and an oil pressure swivel joint The travel motor 13 is connected to an input shaft (not shown) of a transmission 14, and it drives the transmission 14.
A travelling speed detecting pump 17 is provided at the 10 transmission 14, so that the travelling speed detecting pump 17 is rotated in proportion to the rotation of an output shaft of the transmission 14. Pressure oil, which is discharged from the travelling speed detecting pump 17 is fed to a travelling speed detecting motor 18 via the oil pressure swivel joint 15. The 15 travel pump 12 is a variable displacement hydraulic pump, and has capacity control means 12C. The travel motor 13 is a variable displacement hydraulic motor, and has a capacity control means 13C.
A working vehicle (not shown) includes lower 20 travclling equipment (not shown) and an upper revolving superstructure (not shown), and includes a working implement (not shown) at the upper revolving superstructure, and is provided with the oil pressure swivel joint 15 at a connecting part of the lower travelling equipment and the upper revolving 25 superstructure. The engine 11 and a controller 30 are
provided at the upper revolving superstructure, and the transmission 14 is provided at the lower travelling equipment.
The transmission 14 is connected to a gear change valve 16 being gear change control means via the oil pressure 5 swivel joint 15. The gear change valve 16 feeds pressure oil from a transmission pump 19.to a first speed clutch 14F or a second speed clutch 14S via the oil pressure swivel joint 15.
The gear change valve 16 is a two-position switching valve with a simple structure at low cost, and switches a first speed 10 position 16A and a second speed position 16B shown in FIG. 1 according to a gear change signal from the controller 30.
The transmission 14 has a planetary gear mechanism, and according to a pressure signal from the gear change valve 16, it applies pressure to or release the pressure from the first 15 speed clutch 14F for low speed or the second speed clutch 14S for high speed to switch a change gear ratio of the planetary gear mechanism, and engages or disengages it to set the speed gear; The first speed clutch 14F and the second speed clutch 14S are the clutches of a method of applying pressure oil to 20 engage the clutch and releasing the pressure oil to disengage the clutch. The transmission 14 has two speed gears, that is, the first and the second speed gears. When the transmission 14 is made the first speed, the gear change valve 16 is shifted in the first speed position 16A, and the pressure oil from the 25 gear change valve 16 is applied to the first speed clutch 14F to
engage the first speed clutch, and the pressure oil of the second speed clutch 14S is released to disengage the second speed clutch 14S, whereby the transmission 14 is shifted to the first speed. When the transmission 14 is made the second 5 speed, the gear change valve 16 is shifted in the second speed position 16B, and the pressure oil from the gear change valve 16 is applied to the second speed clutch 14S to engage the second speed clutch, and the pressure oil of the first speed clutch 14F is released to disengage the first speed clutch 14F, 10 whereby the transmission 14 is shifted to the second speed.
A vehicle speed detection gear 35 for producing a vehicle speed signal is provided at an output shaft of the vehicle speed detecting motor 18, and is rotated by the vehicle speed detecting motor 18. For example, a predetermined 15 number of teeth, slits and projections and depressions are formed on an outer circumference of the vehicle speed detecting gear 35. A vehicle speed detecting sensor 31 is provided in close vicinity of the outer circumference of the vehicle speed detecting gear 35, and outputs pulse, which 20 occurs when, for example, the predetermined number of teeth on the outer circumference of the vehicle speed detecting gear 35 pass through a signal detecting part of the vehicle speed detecting sensor 31, as an electric signal.
The vehicle speed detecting sensor 31 is connected to 25 the controller 30 and sends the vehicle speed signal to the
controller 30 as an electric signal. Vehicle speed detecting means has the constitution having the vehicle speed detecting gear 35, the vehicle speed detecting sensor 31 and the controller 30 as described above. The controller 30 performs 5 operation processing of the vehicle speed signal to calculate the vehicle speed.
The travelling control valve 21 is switched from a neutral position N to a forward travel position F or a reverse travel position R shown in the drawing, and controls the 10 direction of the pressure oil discharged from the travel pump 12 to send it to the travel motor 13. The travel control valve 21 receives travelling pilot pressure being pilot pressure from a forward and reverse travel switching valve 22 at a froward travel side pressure receiving part 21F or a reverse travel side 15 pressure receiving part 21R, whereby it is switched into the forward travel position F or the reverse travel position R from the neutral position N. The forward and reverse travel switching valve 22 is switched into a forward travel position FK shown in the drawing according to a forward travel signal 20 from the controller 30, and switched into a reverse travel position RK according to a reverse travel signal.
An accelerator pedal 23A is depressed to operate a travelling pilot pressure valve 23 to make it generate travelling pilot pressure. The travelling pilot pressure, 25 which is depressing amount detecting means of the accelerator
pedal 23A, changes according to a depressing amount of the accelerator pedal 23A, and when the depressing amount of the accelerator pedal 23A increases, it increases at a predetermined ratio.
5 A travelling pilot pressure sensor 32 is provided at a circuit between the travelling pilot pressure valve 23 and the forward and reverse travel switching valve 22, and the travelling pilot pressure sensor 32 sends a detected travelling pilot pressure signal to the controller 30. A travelling load 10 pressure sensor 33 being load pressure detecting means is provided at a circuit between the travel pump 12 and the travel control valve 21, and the travelling load pressure sensor 33 sends a detected travelling load pressure signal to the controller. 15 A forward and reverse travel switch 34 is connected to the controller 30 and sends a forward travel command signal or a reverse travel command signal to the controller 30. When the controller 30 receives a travelling pilot pressure signal detected by the travelling pilot pressure sensor 32, it 20 calculates a depressing amount of the accelerator pedal 23A according to the magnitude of the travelling pilot pressure signal. When the controller 30 receives a travelling load pressure signal detected by the travelling load pressure sensor 33 at the circuit between the travel pump 12 and the travel 25 control valve 21, it calculates whether or not the pressure of
the pressure oil discharge by the travel pump 12 exceeds a predctcrmincd value, as a load by travelling resistance.
Further, the controller 30 performs operation processing of the vehicle speed signal being an electric signal, which is detected 5 by the vehicle speed detecting scusor 31 to calculate the vehicle speed. The controller 30 performs operation processing of a variation with time of the vehicle speed, and determines whether it is an accelerating state in which the vehicle speed increases, or a decelerating state in which the 10 vehicle speed decreases.
When the depressing amount of the accelerator pedal 23A, which is calculated according to the magnitude of the aforementioned travelling pilot pressure signal, is a predetermined value or more (for example, the depressing 15 amount of three fourths or more of the total depressing amount of the accelerator pedal 23A), the travailing load pressure signal detected by the travelling load pressure sensor 33 is a predetermined value or more of a maximum set pressure of the travel pump 12 (for example, 80 % or more of the maximum 20 set pressure of the travel pump 12), and the travelling state which is obtained by performing operation processing of the variation with time of the vehicle speed is the deceleration state in which the vehicle speed is decreased, the controller 30 sends a shift-down signal to the gear change valve 16 being 25 the gear change control means. The gear change valve 16
engages the first speed clutch 14F of the transmission 14 and disengages the second speed clutch 14S to operate the first speed clutch 14F, whereby the speed gear is shifted to the first speed gear. The transmission 14 shifts the gear to the 5 forward first speed if the present speed gear is, for example, the forward second speed.
Next, an operation of the automatic transmission apparatus of the hydraulic travelling vehicle of the present embodiment will be explained. When an operator switches 10 the forward and reverse travel switch 34 to the forward travel, the forward and reverse travel switching valve 22 is in the forward position FK, and when the operator depresses the accelerator pedal 23A thereupon, the travelling pilot pressure is applied to the forward travelling side pressure receiving part 15 21F of the travel control valve 21, whereby the travel control valve 21 is switched from the neutral position N to the forward travel position F. First, the controller 30 switches the gear change valve 16 into the first speed position 16A according to the forward 20 travel command signal of the forward and reverse travel switch 34, and the speed gear signal set by a speed gear lever (not shown), for example, the second speed, and engages the first speed clutch 14F and operates it by disengaging the second speed clutch 14S to shift the transmission 14 to the forward 25 first gear. The travel control valve 21 feeds the pressure oil
discharged from the travel pump 12 to a forward travel side port 13F of the travel motor 13 via the oil pressure swivel joint 15. The travel motor rotates in the forward travel direction to drive the transmission 14, whereby the working 5 vehicle travels forward.
When the vehicle speed increases and the vehicle speed signal from the vehicle speed detecting sensor 31 becomes a predetermined value of shifting up to the second speed, the controller 30 sends a shift-up signal being a gear change signal 10 to the gear change valve 16 to switch the gear change valve 16 into the second speed position 16B, and disengages the first speed clutch 14F and engages and operates the second speed clutch 14S, to shift the transmission 14 to the forward second speed gear. Thus, the working vehicle travels at high speed, 15 but when it travels on a slope with an up grade, the travelling resistance increases, thus gradually decreasing the vehicle speed, and the discharge pressure of the travel pump 12 also increases. The operator depresses the accelerator pedal 23A to secure the vehicle speed.
20 When the depressing amount of the accelerator pedal 23A, which is calculated according to the magnitude of the travelling pilot pressure signal, is a predetermined value or more (for example, the depressing amount of three fourths or more of the total depressing amount of the accelerator pedal 25 23A), the travelling load pressure signal detected by the
travelling load pressure sensor 33 is a predetermined value or more of the maximum set pressure of the travel pump 12 (for example, 80 t7O or more of the maximum set pressure of the travel pump 12), and the travelling state which is obtained by 5 performing operation processing of the variation with time of the vehicle speed is the deceleration state in which the vehicle speed is decreased, the controller 30 sends a shift- down signal being a gear change signal to the gear change valve 16 being the gear change control means.
10 The gear change valve 16, which receives the shift-down signal, is switched into the first speed position 16A, disengages the second speed clutch 14S of the transmission 14 via the oil pressure swivel joint 15, and engages and operates the first speed clutch 14F, thereby performing shift-down in 15 which the speed gear is shifted to the forward first speed that is the speed gear lower by one gear. Accordingly, in the hydraulic travailing vehicle being a working vehicle, the optimal speed gear is automatically selected according to the driving state of the vehicle, and it can comfortably travel even 20 on a travel road with large travelling resistance such as a slope with an up grade, without decreasing the vehicle speed drastically. Explanation is made with the transmission 14 including two speed gears of the first speed and the second speed as one 25 example, but the transmission having the speed gears of the
first, second and the third speed gears may be used. Further, the transmission having a plurality of speed gears more than this, for example, four speed gears including the fourth speed, or the transmission having five speed gears further including 5 the fifth speed may be used. The hydraulic travelling vehicle may be a vehicle without having an upper revolving superstructure. The present invention can be also applied to, for example, a wheel loader, a forklift, or the other working vehicles. When the automatic transmission apparatus of the 10 present invention is applied to the vehicle without including the upper revolving superstructure, it is suitable to omit the oil pressure swivel joint 15.
In the above-described embodiment, the first speed clutch 14F for a low speed and the second speed clutch 14S for 15 a high speed of the transmission 14 are the clutches of a method of engaging the clutch by applying the pressure oil and disengaging the clutch by releasing the pressure oil.
However, in contrast with this, it may be suitable to adopt a method of providing springs for connecting a clutch at the first 20 speed clutch 14F for a low speed and the second speed clutch 14S for a high speed, and engaging the clutch by releasing the pressure oil and disengaging the clutch by applying the pressure oil. In this method, when the transmission 14 is shifted to the first speed, the pressure oil to the first speed 25 clutch 14F from the gear change valve 16 is released to engage
the first speed clutch, and the pressure oil is applied to the second speed clutch 14S to disengage the second speed clutch 14S, whereby the transmission 14 is shifted to the first speed.
Meanwhile, when the transmission 14 is shifted to the second 5 speed, the pressure oil to the second speed clutch 14S from the gear change valve 16 is released to engage the second speed clutch, and the pressure oil is applied to the first speed clutch 14F to disengage the first speed clutch 14F, whereby the transmission 14 is shifted to the second speed.
Claims (4)
1. An automatic transmission apparatus of a hydraulic travelling vehicle, comprising: 5 gear change control means of a transmission (14); load pressure detecting means for detecting load pressure of a travel pump (12) for feeding pressure oil to a travel motor (13); vehicle speed detecting means for detecting vehicle 10 speed of the hydraulic travelling vehicle; and a controller (30) which sends a shift-down signal to said gear change control means to shift down said transmission (14), when the load pressure detected by said load pressure detecting means is a predetermined value or more, and it is 15 determined that said hydraulic travelling vehicle is in a decelerating state based on the vehicle speed detected by said vehicle speed detecting means.
2. An automatic transmission apparatus of a hydraulic 20 travelling vehicle, comprising: gear change control means of a transmission (14); depressing amount detecting means for detecting a depressing amount of an accelerator pedal (23A); load pressure detecting means for detecting load 25 pressure of a travel pump (12) for feeding pressure oil to a
travel motor (13); vehicle speed detecting means for detecting vehicle speed of the hydraulic travailing vehicle; and a controller (30) which sends a shift-down signal to 5 said gear change control means to shift down said transmission (14), when the load pressure detected by said load pressure detecting means is a predetermined value or more, the depressing amount detected by said depressing amount detecting means is a predetermined value or more, and it is 10 determined that said hydraulic travelling vehicle is in a decelerating state based on the vehicle speed detected by said vehicle speed detecting means.
3. The automatic transmission apparatus of the hydraulic 15 travelling vehicle according to Claim 1 or Claim 2,
wherein said gear change control means comprises a two-position switching valve (16).
4. The automatic transmission apparatus of the hydraulic 20 travelling vehicle according to any one of Claim 1 to Claim 3, wherein said transmission (14) comprises two travel stages.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0227398A GB2395533B (en) | 2002-11-23 | 2002-11-23 | Automatic transmission apparatus of hydraulic travelling vehicle |
| JP2003380106A JP2004176917A (en) | 2002-11-23 | 2003-11-10 | Automatic transmission for hydraulic running vehicle |
| FR0313415A FR2847635B1 (en) | 2002-11-23 | 2003-11-17 | DEVICE FOR AUTOMATIC TRANSMISSION OF MOBILE VEHICLE |
| DE10354196A DE10354196B4 (en) | 2002-11-23 | 2003-11-20 | Automatic transmission of a hydraulic vehicle |
| CN200310116448A CN100575748C (en) | 2002-11-23 | 2003-11-21 | The automatic transimission of oil pressure moving vehicle |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0227398A GB2395533B (en) | 2002-11-23 | 2002-11-23 | Automatic transmission apparatus of hydraulic travelling vehicle |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB0227398D0 GB0227398D0 (en) | 2002-12-31 |
| GB2395533A true GB2395533A (en) | 2004-05-26 |
| GB2395533B GB2395533B (en) | 2006-10-04 |
Family
ID=9948420
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0227398A Expired - Fee Related GB2395533B (en) | 2002-11-23 | 2002-11-23 | Automatic transmission apparatus of hydraulic travelling vehicle |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JP2004176917A (en) |
| CN (1) | CN100575748C (en) |
| DE (1) | DE10354196B4 (en) |
| FR (1) | FR2847635B1 (en) |
| GB (1) | GB2395533B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8554423B2 (en) | 2005-06-03 | 2013-10-08 | Hitachi Construction Machinery Co., Ltd. | Automatic transmission device for wheel loader and wheel loader |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1944135B (en) * | 2005-10-08 | 2013-03-20 | 比亚迪股份有限公司 | Automobile control system |
| DE102009006468A1 (en) * | 2009-01-29 | 2010-08-05 | Robert Bosch Gmbh | Method and device for changing gears of a hydrostatically driven multi-speed transmission |
| CN110985629B (en) * | 2019-12-26 | 2023-02-17 | 广西柳工机械股份有限公司 | Hydrostatic drive transmission system, speed change control method and loader |
| DE102022210771A1 (en) | 2022-10-12 | 2024-04-18 | Scheuerle Fahrzeugfabrik Gmbh | Drive and transport vehicle |
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| US6123644A (en) * | 1999-07-19 | 2000-09-26 | Eaton Corporation | Adaptive anti-hunt logic for automated transmission downshift control |
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| US4185521A (en) * | 1975-03-10 | 1980-01-29 | Caterpillar Tractor Co. | Hydraulic control system for a hydrostatic-mechanical transmission |
| DE3807599A1 (en) * | 1988-03-08 | 1989-09-28 | Hydromatik Gmbh | AUTOMOTIVE DRIVE DEVICE FOR MACHINES AND VEHICLES |
| DE4223846C2 (en) * | 1992-07-20 | 1996-03-28 | Hydromatik Gmbh | Gear unit for arrangement between a drive motor and a consumer |
| DE4417335A1 (en) * | 1993-06-01 | 1995-03-16 | Michael Meyerle | Continuously variable hydrostatic/mechanical split-torque transmission |
| US6295497B1 (en) * | 1999-10-27 | 2001-09-25 | Caterpillar Inc. | Method and apparatus for adaptively shifting ranges in a continuously variable transmission |
| US6481314B2 (en) * | 2000-01-07 | 2002-11-19 | Kanzaki Kokyukoki Mfg. Co. Ltd. | Vehicle travelling control apparatus |
-
2002
- 2002-11-23 GB GB0227398A patent/GB2395533B/en not_active Expired - Fee Related
-
2003
- 2003-11-10 JP JP2003380106A patent/JP2004176917A/en active Pending
- 2003-11-17 FR FR0313415A patent/FR2847635B1/en not_active Expired - Fee Related
- 2003-11-20 DE DE10354196A patent/DE10354196B4/en not_active Expired - Fee Related
- 2003-11-21 CN CN200310116448A patent/CN100575748C/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6123644A (en) * | 1999-07-19 | 2000-09-26 | Eaton Corporation | Adaptive anti-hunt logic for automated transmission downshift control |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8554423B2 (en) | 2005-06-03 | 2013-10-08 | Hitachi Construction Machinery Co., Ltd. | Automatic transmission device for wheel loader and wheel loader |
Also Published As
| Publication number | Publication date |
|---|---|
| DE10354196B4 (en) | 2008-06-05 |
| GB2395533B (en) | 2006-10-04 |
| GB0227398D0 (en) | 2002-12-31 |
| CN100575748C (en) | 2009-12-30 |
| FR2847635B1 (en) | 2006-05-19 |
| JP2004176917A (en) | 2004-06-24 |
| FR2847635A1 (en) | 2004-05-28 |
| CN1502495A (en) | 2004-06-09 |
| DE10354196A1 (en) | 2004-06-03 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| COOA | Change in applicant's name or ownership of the application |
Owner name: KOMATSU LTD Free format text: FORMER APPLICANT(S): KOMATSU UK LIMITED |
|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20131123 |