JP6904180B2 - transmission - Google Patents

Description

The present invention relates to a transmission.

Conventionally, a hydraulic mechanical continuously variable transmission (hydromechanical transmission: HMT), which is a combination of a hydrostatic continuously variable transmission (HST) and a differential mechanism, is known (for example, Patent Document 1). See). Patent Document 1 discloses a so-called "input split type" HMT in which a driving force from an engine is split by a planetary gear mechanism and input to two hydraulic pump motors.

Japanese Patent No. 2522219

In the HMT described in Patent Document 1, one hydraulic pump motor is connected to the first output element of the planetary gear mechanism via the first reduction mechanism, and the second output element of the planetary gear mechanism is connected to the second output element. The other hydraulic pump motor is connected via the reduction mechanism of 2.

Therefore, it is necessary to arrange both hydraulic pump motors on an axis different from the output shaft of the engine, and there is a problem that the overall structure is three-axis and the size is increased in the radial direction.

An object of the present invention is to provide a transmission capable of suppressing an increase in size in the radial direction.

The transmission according to the present invention includes an input shaft into which the rotational force of the drive source is input, a reduction mechanism for transmitting the rotational force of the input shaft to the differential mechanism, and the transmission divided into two by the differential mechanism. A hydraulic transmission in which one variable displacement pump motor to which one of the rotational forces is input and the other variable capacitance pump motor to which the other is input are connected by a closed circuit, and one of the variable capacitance pump motors are turned on. A first engaging mechanism capable of outputting the rotational force of the output shaft to the output shaft, and a second engaging mechanism capable of outputting the rotational force of the input / output shaft of the other variable displacement pump motor to the output shaft. The input / output shaft of one of the variable displacement pump motors is provided coaxially with the input shaft.

According to the transmission according to the present invention, it is possible to prevent the transmission from becoming larger in the radial direction.

A skeleton diagram showing the overall configuration of a vehicle according to an embodiment of the present invention. Skeleton diagram showing the first transmission state Skeleton diagram showing the second transmission state Skeleton diagram showing the third transmission state The figure which shows the relationship between the speed ratio and the push-out volume

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The embodiment described below is an example, and the present invention is not limited to this embodiment.

First, with reference to FIG. 1, the overall configuration of the vehicle 1 equipped with the hydraulic mechanical transmission according to the present embodiment will be described. In FIG. 1, the front-rear direction of the vehicle 1 is drawn. In the following description, the front side of the vehicle may be simply referred to as "front" and the rear side of the vehicle may be simply referred to as "rear".

The vehicle 1 includes a drive source 10, a damper 20, a differential mechanism 30, a hydraulic transmission 40, and a stepped transmission 50. A drive wheel 64 is connected to the output side of the stepped transmission 50 via a propeller shaft 61, a differential 62, and a drive shaft 63 so that power can be transmitted.

The drive source 10 is, for example, a diesel engine. The drive source 10 may be a gasoline engine, an electric motor, or the like. The input side member 21 of the damper 20 is connected to the output shaft 11 of the drive source 10.

The damper 20 includes an input side member 21, an output side member 22, and an elastic connecting member 23 that elastically connects the input side member 21 and the output side member 22. The output side member 22 of the damper 20 is connected to the input shaft 22a. The damper 20 has a function of suppressing the rotational vibration generated by the drive source 10 from being transmitted to the differential mechanism 30. Since the structure of the damper 20 is the same as that of a general damper, detailed description thereof will be omitted.

The rear end of the input shaft 22a is pivotally supported by a second input / output shaft 42a (described later) via a bearing (not shown). The input shaft 22a and the second input / output shaft 42a are arranged coaxially.

A reduction gear 22b is provided on the rear end side of the input shaft 22a so as to rotate integrally with the input shaft 22a. The reduction gear 22b meshes with the differential input gear 31a provided on the outer periphery of the input member 31 of the differential mechanism 30. The reduction mechanism 24 is configured by the reduction gear 22b and the differential input gear 31a. The rotation of the drive source 10 transmitted to the input shaft 22a is decelerated by the deceleration mechanism 24 and input to the differential mechanism 30.

The differential mechanism 30 includes a plurality of bevel gears 32, a first differential output gear 33, and a second differential output gear 34 provided evenly arranged in the circumferential direction. As shown in FIG. 1, the bevel gear 32 is pivotally supported by the input member 31 so as to be relatively rotatable. The first differential output gear 33 is provided at the front end of the first input / output shaft 41a of the first pump motor 41. The second differential output gear 34 is provided at the front end of the differential output shaft 35.

The differential output shaft 35 is a cylindrical member coaxial with the first input / output shaft 41a and provided on the outer peripheral side of the first input / output shaft 41a. A first gear 36 is provided at the rear end of the differential output shaft 35. The differential output shaft 35 is pivotally supported by the first input / output shaft 41a via a bearing (not shown). The first gear 36 meshes with the second gear 37 provided on the front end side of the second input / output shaft 42a of the second pump motor 42.

In the present embodiment, the number of teeth of the first differential output gear 33 is the same as the number of teeth of the second differential output gear 34. Further, the number of teeth of the first gear 36 is the same as the number of teeth of the second gear 37. Since the structure of the differential mechanism 30 is the same as that of a general bevel gear type differential mechanism, detailed description thereof will be omitted.

Here, the reason why the output shaft 11 of the drive source 10 is not directly connected to the differential mechanism 30 via the damper 20 but is connected via the reduction mechanism 24 including the reduction gear 22b and the differential input gear 31a is simple. Explain to.

As described above, in the present embodiment, the power of the drive source 10 is input to the input member 31 that pivotally supports the bevel gear 32, and is output from the first differential output gear 33 and the second differential output gear 34. Therefore, any one of the first differential output gear 33 and the second differential output gear 34, unless the rotation speeds of the input member 31, the first differential output gear 33, and the second differential output gear 34 are the same. One rotation speed exceeds the rotation speed of the input member 31.

Therefore, when the output shaft 11 of the drive source 10 is directly connected to the input member 31 of the differential mechanism 30, the upper limit of the rotation speed of the drive source 10 is the first pump motor 41 and the second pump motor 42 of the hydraulic transmission unit 40 ( It may be limited by the upper limit rotation speed of (described later).

On the other hand, in the present embodiment, the rotation speed of the output shaft 11 of the drive source 10 is decelerated and transmitted to the input member 31 of the differential mechanism 30. Therefore, it is possible to preferably suppress that the upper limit of the rotation speed of the drive source 10 is limited by the upper limit rotation speed of the first pump motor 41 and the second pump motor 42.

A reduction mechanism is provided between the first and second differential output gears 33 and 34 and the first and second pump motors 41 and 42, respectively, to rotate the first and second differential output gears 33 and 34. It is conceivable to decelerate the number and transmit it to the first and second pump motors 41 and 42.

However, in such a case, it is necessary to provide an additional shaft on an axis different from the first and second input / output shafts 41a and 42a in order to provide the reduction mechanism, and the transmission becomes larger in the radial direction. Also, two deceleration mechanisms are required.

On the other hand, in the present embodiment, the input shaft 22a is arranged coaxially with the second input / output shaft 42a, and the axis of the differential mechanism 30 is aligned with the first input / output shaft 41a. Therefore, the transmission as a whole has a two-axis structure, and it is possible to preferably suppress the transmission from becoming larger in the radial direction. There is also one deceleration mechanism.

The hydraulic transmission 40 includes a first pump motor 41, a second pump motor 42, and a closed circuit 43 that hydraulically connects the first pump motor 41 and the second pump motor 42. Since the configuration of the closed circuit 43 is the same as that of a general HST closed circuit, the components (charge pump, charge oil passage, relief oil passage, bypass oil passage, etc.) in the closed circuit 43 are omitted in FIG. doing.

The first pump motor 41 is a so-called double swing type pump motor capable of changing the push-out volume from zero to both positive and negative directions. The first input / output shaft 41a of the first pump motor 41 penetrates the first pump motor 41 from front to back. As such a first pump motor 41, various types such as an axial piston type and a radial piston type can be adopted. The first pump motor 41 corresponds to the "other variable displacement pump motor" of the present invention.

The second pump motor 42 is a so-called double swing type pump motor capable of changing the push-out volume from zero to both positive and negative directions. The second input / output shaft 42a of the second pump motor 42 penetrates the second pump motor 42 from front to back. As such a second pump motor 42, various types such as an axial piston type and a radial piston type can be adopted. The second pump motor 42 corresponds to the "one variable displacement pump motor" of the present invention.

In this embodiment, the first pump motor 41 and the second pump motor 42 have the same type. Further, the maximum push-out volume of the first pump motor 41 is equal to the maximum push-out volume of the second pump motor 42.

The stepped speed change unit 50 includes a first input / output shaft 41a, a second input / output shaft 42a arranged in parallel with the first input / output shaft 41a, a sub shaft 51, and an output shaft 52. The first input / output shaft 41a corresponds to the "input / output shaft of the other variable displacement pump motor" of the present invention. The second input / output shaft 42a corresponds to the "input / output shaft of one variable displacement pump motor" of the present invention.

As described above, the first differential output gear 33 of the differential mechanism 30 is provided at the front end of the first input / output shaft 41a. Further, at the rear end of the first input / output shaft 41a, a first input hub 41b is provided so as to rotate integrally with the first input / output shaft 41a.

The sub-shaft 51 is a cylindrical member coaxial with the first input / output shaft 41a and provided on the outer peripheral side of the first input / output shaft 41a. A first sub gear 53 is provided at the front end of the sub shaft 51, and a second sub gear 54 is provided at the rear end of the sub shaft 51.

The first input / output gear 55 is provided on the outer peripheral side of the first input / output shaft 41a so as to be rotatable relative to the first input / output shaft 41a. The first input gear 55 is provided between the sub-shaft 51 and the first input hub 41b.

As described above, the second gear 37 of the differential mechanism 30 is provided on the front end side of the second input / output shaft 42a. A second input / output hub 42b is provided at the rear end of the second input / output shaft 42a so as to rotate integrally with the second input / output shaft 42a.

The second input gear 56 is provided so as to rotate integrally with the second input / output shaft 42a. The second input gear 56 is provided between the second pump motor 42 and the second input hub 42b. The second input gear 56 meshes with the first sub gear 53.

An output hub 57 is provided at the front end of the output shaft 52 so as to rotate integrally with the output shaft 52. The first output gear 58 is provided on the outer peripheral side of the output shaft 52 so as to be rotatable relative to the output shaft 52. The first output gear 58 is provided on the rear side of the output hub 57. The first output gear 58 meshes with the second sub gear 54.

The second output gear 59 is provided so as to rotate integrally with the output shaft 52. The second output gear 59 is provided on the rear side of the first output gear 58. The second output gear 59 meshes with the first input gear 55.

The stepped speed change unit 50 is provided with a first connecting mechanism 71 that selectively connects the first input / output shaft 41a and the first input gear 55 so as to be integrally rotatable. The first connecting mechanism 71 includes a first input hub 41b, a first clutch gear 55a provided integrally with the first input gear 55, and a first sleeve 72.

The first sleeve 72 is provided on the outer peripheral side of the first input hub 41b so as to be integrally rotatable with the first input hub 41b and relatively movable in the axial direction. When the first sleeve 72 is in the rear position shown in FIG. 1, the first input / output shaft 41a and the first input gear 55 can rotate relative to each other.

By setting the first sleeve 72 in the front position, the first input gear 55 rotates integrally with the first input / output shaft 41a. In this embodiment, a general synchronizer type is used as the first connecting mechanism 71. Since the synchronizer type connection mechanism is known, detailed description thereof will be omitted. The first connecting mechanism 71 corresponds to the "second engaging mechanism" of the present invention.

The stepped transmission 50 is provided with a second connecting mechanism 73 that selectively connects the second input / output shaft 42a and the output shaft 52, or the first output gear 58 and the output shaft 52 so as to be integrally rotatable. ing. The second connecting mechanism 73 includes a second input hub 42b, an output hub 57, an output clutch gear 58a provided integrally with the first output gear 58, and a second sleeve 74.

The second sleeve 74 is provided on the outer peripheral side of the output hub 57 so as to be integrally rotatable with the output hub 57 and relatively movable in the axial direction. When the second sleeve 74 is in the central position shown in FIG. 1, the second input / output shaft 42a and the output shaft 52 can rotate relative to each other. Further, when the second sleeve 74 is in the central position shown in FIG. 1, the first output gear 58 and the output shaft 52 can rotate relative to each other.

By setting the second sleeve 74 in the front position, the output shaft 52 rotates integrally with the second input / output shaft 42a. Further, by setting the second sleeve 74 at the rear position, the output shaft 52 rotates integrally with the first output gear 58. The second connecting mechanism 73 corresponds to the "first engaging mechanism" of the present invention.

Here, the first sleeve 72 is set to the rear position and the second sleeve 74 is set to the rear position, and the rotation of the second input / output shaft 42a is the second input gear 56, the first sub gear 53, and the second sub gear 54. The state transmitted to the output shaft 52 via the first output gear 58 is referred to as a "first transmission state" (see FIG. 2).

Further, the first sleeve 72 is set to the front position and the second sleeve 74 is set to the center position, and the rotation of the first input / output shaft 41a passes through the first input gear 55 and the second output gear 59 to the output shaft 52. The state transmitted to is referred to as "second transmission state" (see FIG. 3).

Further, the state in which the first sleeve 72 is set to the rear position and the second sleeve 74 is set to the front position and the rotation of the second input / output shaft 42a is directly transmitted to the output shaft 52 is referred to as a "third transmission state" or. It is called "direct connection state" (see FIG. 4).

In the present embodiment, the number of teeth of the second input gear 56, the first sub gear 53, the second sub gear 54, and the first output gear 58 is such that the rotation of the second input / output shaft 42a is decelerated in the first transmission state. It is set so that it is transmitted to the output shaft 52. Further, the number of teeth of the first input gear 55 and the second output gear 59 is set so that the rotation of the first input / output shaft 41a is decelerated and transmitted to the output shaft 52 in the second transmission state. ..

The gear ratio in the first transmission state (rotation speed of the second input / output shaft 42a / rotation speed of the output shaft 52) is α1, and the gear ratio in the second transmission state (rotation speed of the first input / output shaft 41a / rotation speed of the output shaft 52). If the number of rotations) is α2, then α1> α2> 1. The relationship between α1, α2 and 1 (directly connected) is not limited to this. Specifically, for example, α1 <α2 <1 can be set.

Next, the shifting operation will be described with reference to FIGS. 2 to 5. 2 to 4 are skeleton diagrams in each transmission state. FIG. 5 is a diagram showing the relationship between the speed ratio and the push-out volume.

The vehicle 1 is started in the first transmission state shown in FIG. In this case, the first pump motor 41 operates as a pump, and the second pump motor 42 operates as a motor. In the following description, "operates as a pump" and "operates as a motor" are the first pumps when the vehicle 1 is driven by the drive source 10 (that is, when the tires are doing a positive job). It refers to the roles of the motor 41 and the second pump motor 42. When the vehicle 1 is driven from the wheel side (that is, when the engine brake is applied), the roles of the pump and the motor are reversed.

In order to start the vehicle 1, the pressing volume of the first pump motor 41 operating as a pump is gradually increased from zero while the pressing volume of the second pump motor 42 is held to the maximum. By doing so, as shown in FIG. 5, the speed ratio (rotation speed Nout of the output shaft 52 / rotation speed Nin of the drive source 10) increases from zero.

At this time, when the engine torque is controlled so that the discharge pressure from the first pump motor 41 to the second pump motor 42 becomes constant (that is, the engine torque is increased according to the increasing pump-side push-out volume). In this case), the torque generated by the second pump motor 42 becomes constant. Further, the torque transmitted from the differential gear to the second input / output shaft 42a of the second pump motor 42 increases. Therefore, the torque transmitted to the output shaft 52 increases.

When the push-out volume of the first pump motor 41 becomes maximum, the push-out volume of the second pump motor 42 operating as a motor is gradually set to zero while keeping the push-out volume of the first pump motor 41 at the maximum. To reduce. By doing this, the speed ratio will increase further.

The pressing volume of the second pump motor 42 is gradually reduced, and when the pressing volume of the second pump motor 42 becomes Q1, the rotation speed of the first input hub 41b (that is, the rotation of the first input / output shaft 41a). Number) and the rotation speed of the first input gear 55 match.

At this timing, the stepped transmission unit 50 shifts gears. Specifically, the first sleeve 72 is moved to the front position, and the second sleeve 74 is moved from the rear position to the center position. In this way, the stepped speed change unit 50 shifts from the first transmission state to the second transmission state. It should be noted that torque is not cut off during such shifting.

When the stepped transmission 50 completes the shift from the first transmission state to the second transmission state, the first pump motor 41, which was operating as a pump in the first transmission state, operates as a motor and operates as a motor. The second pump motor 42, which had been used, will operate as a pump.

Subsequently, while the push-out volume of the first pump motor 41 is held to the maximum, the push-out volume of the second pump motor 42 that operates as a pump is gradually increased from Q1. By doing this, the speed ratio will increase further.

When the squeeze volume of the second pump motor 42 becomes maximum, the squeeze volume of the first pump motor 41 operating as a motor is gradually reduced to zero while maintaining the squeeze volume of the second pump motor 42 to the maximum. To reduce. By doing this, the speed ratio will increase further.

The push-out volume of the first pump motor 41 is gradually reduced, and when the push-out volume of the first pump motor 41 becomes Q2, the rotation speed of the second input hub 42b (that is, the rotation of the second input / output shaft 42a). The number) and the rotation speed of the output hub 57 (that is, the rotation speed of the output shaft 52) match.

At this timing, the stepped transmission unit 50 shifts gears. Specifically, the second sleeve 74 is moved to the front position, and the first sleeve 72 is moved from the front position to the rear position. In this way, the stepped speed change unit 50 shifts from the second transmission state to the third transmission state. It should be noted that torque is not cut off during such shifting.

When the stepped transmission 50 completes the shift from the second transmission state to the third transmission state, the second pump motor 42, which was operating as a pump in the second transmission state, operates as a motor and operates as a motor. The first pump motor 41, which had been used, will operate as a pump.

Subsequently, the pressing volume of the first pump motor 41 operating as a pump is gradually increased from Q2 while the pressing volume of the second pump motor 42 is held to the maximum. By doing this, the speed ratio will increase further.

When the push-out volume of the first pump motor 41 becomes maximum, the push-out volume of the second pump motor 42 operating as a motor is gradually set to zero while keeping the push-out volume of the first pump motor 41 at the maximum. To reduce. By doing this, the speed ratio will increase further. Then, the speed ratio increases until the pressing volume of the second pump motor 42 becomes substantially zero.

As described above, according to the present embodiment, the rotational force of the drive source 10 is input from the input shaft 22a coaxially arranged with the second input / output shaft 42a to the differential mechanism 30 via the reduction mechanism 24. It is transmitted to the member 31. As a result, the transmission can have a two-axis structure. Therefore, it is possible to suppress the increase in size in the radial direction.

In particular, when the transmission is mounted on a so-called FR vehicle in which the engine is arranged on the front side of the vehicle and the rear wheels are the driving wheels, the radial dimensions are often restricted in terms of vehicle mounting. In the present embodiment, since the transmission has a two-axis structure as a whole, the mountability on an FR vehicle is improved. Further, when the transmission is arranged vertically with respect to the vehicle, the radial dimension of the transmission is often restricted in relation to the space for mounting the transmission (particularly the space in the vehicle width direction). In particular, when a side PTO is added to the transmission or when the vehicle is four-wheel drive, there are large restrictions on the radial dimensions of the transmission. According to the transmission of the present embodiment, since it has a two-axis structure, it is possible to suppress an increase in size in the radial direction, and when the transmission is installed vertically with respect to the vehicle, the mountability on the vehicle is improved. To do.

Further, according to the present embodiment, a second connecting mechanism 73 is provided which shifts the rotation of the second input / output shaft 42a of the second pump motor 42 and transmits the rotation to the output shaft 52. Therefore, the vehicle can travel at high speed.

Further, according to the present embodiment, the first connecting mechanism 71 and the second connecting mechanism 73 are mechanical engaging mechanisms by engaging the hub and the sleeve. Therefore, the loss of transmission efficiency can be reduced.

In the above-described embodiment, the input shaft 22a is arranged coaxially with the second input / output shaft 42a, and the axis of the differential mechanism 30 is aligned with the first input / output shaft 41a, but the present invention is not limited to this. The input shaft 22a may be arranged coaxially with the first input / output shaft 41a, and the axis of the differential mechanism 30 may be aligned with the second input / output shaft 42a.

Further, in the above-described embodiment, the differential mechanism is a bevel gear type differential mechanism, but the present invention is not limited to this. As the differential mechanism, a known structure can be appropriately adopted. Specifically, for example, a planetary gear mechanism can be used as the differential mechanism.

Further, in the above-described embodiment, the stepped transmission has a total of three speeds, with the first input / output shaft side having one speed and the second input / output shaft side having two speeds, but the present invention is not limited to this. Specifically, for example, the first input / output shaft may have two stages and the first input / output shaft side may have one stage.

Further, in the present embodiment, the number of gears in the stepped gearbox is set to 3, but the present invention is not limited to this. Specifically, for example, a transmission mechanism for shifting the rotational force of the first input / output shaft and transmitting it to the output shaft is provided, and a total of four stages, two stages on the first input / output shaft side and two stages on the second input / output shaft side, are provided. May be. In this case, each gear ratio is set so that the first input / output shaft and the second input / output shaft are used alternately. Further, it is possible to increase the number of gears from each input / output shaft to the output shaft by 3 or more.

The continuously variable transmission of the present invention is suitably used for a vehicle in which the transmission is installed vertically with respect to the vehicle, particularly in a so-called FR vehicle in which the engine is arranged on the front side of the vehicle and the rear wheels are the driving wheels.

1 Vehicle 10 Drive source 11 Output shaft 20 Damper 21 Input member 22 Output side member 22a Input shaft 22b Reduction gear 23 Elastic coupling member 24 Deceleration mechanism 30 Differential mechanism 31 Input member 31a Differential input gear 32 Bevel gear 33 First differential Output gear 34 2nd differential output gear 35 Differential output shaft 36 1st gear 37 2nd gear 40 Hydraulic transmission 41 1st pump motor 41a 1st input / output shaft 41b 1st input hub 42 2nd pump motor 42a 2nd Input / output shaft 42b 2nd input hub 43 Closed circuit 50 Stepped speed change part 51 Sub shaft 52 Output shaft 53 1st sub gear 54 2nd sub gear 55 1st input gear 55a 1st clutch gear 56 2nd input gear 57 Output hub 58 1st output gear 58a Output clutch gear 59 2nd output gear 61 Propeller shaft 62 Differential 63 Drive shaft 64 Drive wheel 71 1st connection mechanism 72 1st sleeve 73 2nd connection mechanism 74 2nd sleeve

Claims (3)

The input shaft to which the rotational force of the drive source is input, and
A deceleration mechanism that transmits the rotational force of the input shaft to the differential mechanism,
A hydraulic transmission unit in which one of the variable displacement pump motors to which one of the rotational forces divided by the differential mechanism is input and the other variable displacement pump motor to which the other is input are connected by a closed circuit. When,
The first engaging mechanism capable of outputting the rotational force of the input / output shaft of the one variable displacement pump motor to the output shaft, and the rotational force of the input / output shaft of the other variable displacement pump motor to the output shaft. A stepped speed change unit having a second engaging mechanism capable of outputting is provided.
The input / output shafts of the one variable displacement pump motor are arranged coaxially with the input shafts.
transmission. The first engaging mechanism can shift the rotational force of the input / output shaft of the one variable displacement pump motor at a plurality of gear ratios and output it to the output shaft.
The transmission according to claim 1. The first and second engaging mechanisms are mechanical engaging mechanisms.
The transmission according to claim 1 or 2.

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