JP2007078160A - Hydraulic-mechanical transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an output-split type HMT (hydro mechanical transmission) wherein driving by HMT is possible in all speed regions including low speed and reverse shift, and thereby the load applied to the HST can be reduced, a wide speed range is secured even in low speed and reverse shift, and enhanced power transmitting efficiency can be exhibited. <P>SOLUTION: In HMT 57 equipped with HST 52 and a planetary gear mechanism on a rear stage of a driving source so as to output composite power and mounted on a work vehicle, a low speed transmission mechanism 5 comprising a low speed shifting planetary gear 8 and a low speed clutch 11, a high speed transmission mechanism 6 comprising a high speed shifting planetary gear 9 and a high speed clutch 12, and a reverse transmission mechanism 7 comprising a reverse shifting planetary gear 10 and a reverse clutch 13 are arranged on a same axis. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technology of a hydraulic-mechanical transmission device including a hydraulic continuously variable transmission mechanism and a planetary gear mechanism.

Conventionally, as a vehicle drive technology, a hydraulic continuously variable transmission (HST) and a hydraulic-mechanical transmission (HMT) equipped with a differential mechanism have been known and have high efficiency. Since it can be achieved and is suitable as a transmission for heavy vehicles that require forward and backward travel, it has been widely produced and used. (Hereinafter, the hydraulic continuously variable transmission mechanism is described as HST, and the hydraulic-mechanical transmission is described as HMT.)
As a typical configuration of the HMT, there is one using a set of planetary gear mechanisms as the differential mechanism. Specifically, rotational power is input to one of the three elements (first element) of the sun gear, internal gear, and planetary carrier that constitute the planetary gear mechanism, and the other element (second The output rotation is taken out from the other element), and the output or input to the HST is linked from the remaining one element (third element).
As described in Patent Document 1, HMT is classified into an output division type and an input division type, and each type has advantages and disadvantages. In the output division type, there is a power circulation region in the vicinity where the rotation of the output shaft becomes zero, so there is generally a problem in power transmission efficiency during low speed and reverse travel.
Therefore, in a transmission employing a conventional output division type HMT, as described in Patent Document 2, in order to solve the above-mentioned problem and realize delicate speed control in a low speed range, only HST is used at low speed and reverse speed. There has been proposed a switchable mechanism for driving.
However, even in this system, when the weight of the vehicle is large, there is a problem that the burden on the HST becomes large, and the speed range in which the vehicle can travel with the driving force of the HST becomes small, and the speed at low speed and reverse is increased. Is difficult.
JP 2001-355705 A JP 2003-130174 A

  Therefore, in view of the above situation, the present invention reduces the burden on HST by adopting a configuration that can be driven by HMT in all speed ranges including low speed and reverse, and at low speed and reverse It is an object of the present invention to provide a transmission device using an output division type HMT that secures a wide speed range and has good power transmission efficiency.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  That is, according to the first aspect of the present invention, in the HMT provided in the work vehicle provided with the hydraulic continuously variable transmission and the planetary gear mechanism at the subsequent stage of the drive source and outputting the combined power, A low speed transmission mechanism comprising a low speed planetary gear and a low speed clutch, a high speed transmission mechanism comprising a high speed planetary gear and a high speed clutch, and a reverse transmission mechanism comprising a reverse planetary gear and a reverse clutch. It is characterized by that.

  In claim 2, the power from the engine is transmitted to the sun gear of the planetary gear for low speed transmission, the power shifted by HST is transmitted to the internal gear of the planetary gear for high speed transmission, and power is supplied to each clutch from a common carrier. It is characterized by having a transmission structure.

  According to a third aspect of the present invention, the carrier shaft of the low-speed transmission planetary gear, the carrier shaft of the high-speed transmission planetary gear, and the carrier shaft of the reverse transmission planetary gear are integrally configured. .

  According to a fourth aspect of the present invention, the HMT is arranged from the upstream side of the drive with a low speed planetary gear, a high speed planetary gear, a high speed clutch, a low speed clutch, a reverse transmission planetary gear, and a reverse clutch. It is what.

  As effects of the present invention, the following effects can be obtained.

  According to the first aspect of the present invention, the speed change range in each mode is changed from the normal rotation position to the reverse rotation position by individually providing a shift mechanism adapted to each of the low speed, high speed, and reverse shift modes. Since it is possible to shift within the range up to, it is possible to increase the shift range in each mode and to increase the gear ratio. In addition, planetary gears, clutches, and the like can be compactly arranged on the same axis, and the mission case can be downsized.

  According to the second aspect of the present invention, each of the low speed, high speed, and reverse shift modes can be configured with a simple configuration. Further, switching between the modes is simple and easy to understand.

  According to the third aspect of the present invention, the carrier shafts of the three planetary gears are integrated, and the planetary gears can be disposed close to each other, thereby enabling a compact device configuration.

  According to the fourth aspect of the present invention, since the speed is reduced by the planetary gear, the axial direction can be shortened, and a compact transmission can be configured. Further, the hydraulic clutches can be arranged side by side in the axial direction, and the configuration of the hydraulic piping can be simplified.

Next, embodiments of the invention will be described.
FIG. 1 is a skeleton diagram showing a drive configuration of a work vehicle according to an embodiment of the present invention, FIG. 2 is a sectional view of a mission portion showing the configuration of an HMT according to an embodiment of the present invention, and FIG. FIG. 4 is a correlation diagram showing the relationship between the rotational speeds of the HST motor output shaft and the HMT output shaft according to one embodiment of the present invention.
2 and 3, the direction of arrow A is the front for convenience of description, and the opposite direction is the rear.

  In the following description, in the HMT 57 provided in the work vehicle that includes the HST 52 and the planetary gear mechanism in the subsequent stage of the drive source and outputs the combined power, the planetary gear 8 for low speed transmission is arranged on the same axis. A low speed transmission mechanism 5 composed of a low speed clutch 11, a high speed transmission planetary gear 9 and a high speed transmission mechanism 6 composed of a high speed clutch 12, and a reverse transmission mechanism 7 composed of a reverse transmission planetary gear 10 and a reverse clutch 13. It is characterized by the arrangement.

  As shown in FIGS. 1 to 3, the transmission 1 is covered with a mission case 50, and an input shaft 2, an HST output shaft 3, a composite output shaft 4, etc. are parallel to the mission case 50 in the front-rear direction. Arranged and supported rotatably. The rotational output of the engine 51 is transmitted to the input shaft 2 via the damper 58.

  Further, in the transmission case 50, the low-speed shift planetary gear 8, the high-speed shift planetary gear 9, and the reverse shift planetary gear 10 are rotatable in parallel and in the front-rear direction with the combined output shaft 4 as the same axis. It is supported. Similarly, the low speed clutch 11, the high speed clutch 12, and the reverse clutch 13 are supported in parallel and in the front-rear direction, with the combined output shaft 4 as the same axis.

  The low speed transmission planetary gear 8 and the low speed clutch 11 constitute a low speed transmission mechanism 5, and the high speed transmission planetary gear 9 and the high speed clutch 12 constitute a high speed transmission mechanism 6. The reverse transmission mechanism 7 is constituted by the clutch 13.

  In addition, as shown in FIG. 3, by providing a speed change mechanism having independent speed ratios in each of the low speed, high speed, and reverse modes, the speed range in each mode can be widened.

That is, by individually providing a shift mechanism corresponding to each of the low speed, high speed, and reverse shift modes, the shift range in each mode is within the range from the forward rotation position to the reverse rotation position of the swash plate of the hydraulic pump 53 of the HST 52. Therefore, the speed change range in each mode can be increased and the gear ratio can be increased.
Further, the planetary gears 8, 9, 10 and the clutches 11, 12, 13 and the like can be arranged in a compact manner on the same axis, and the mission case 50 can be downsized.

  Next, in the following explanation, power from the engine is transmitted to the low speed sun gear 16 of the low speed planetary gear 8, and the power shifted by the HST 52 is transmitted to the low and high speed internal gear 18 of the high speed planetary gear 9. The power transmission is transmitted from the common planetary carrier 17 to each of the clutches 11, 12, and 13.

First, details of the low speed transmission mechanism 5 and the high speed transmission mechanism 6 will be described.
As shown in FIGS. 1 to 3, the HST 52 includes a hydraulic pump 53 and a hydraulic motor 54, and the hydraulic pump 53 and the hydraulic motor 54 are attached to a flat plate-shaped center plate 55 and are covered by an HST housing 56. . The center plate 55 is fixed in front of the mission case 50. An input shaft 2 that transmits power from the engine 51 that is a drive source is inserted and penetrated through the rotational axis of the hydraulic pump 53 of the HST 52. Further, the HST output shaft 3 for transmitting the power from the HST 52 is inserted into the rotating shaft core of the hydraulic motor 54 of the HST 52 and protrudes to the rear side of the HST 52. The hydraulic pump 53 is a variable displacement type, and the discharge amount and the discharge direction can be changed by tilting the movable swash plate 53a. The hydraulic motor 54 is a fixed capacity type.

As shown in FIG. 2, the planetary gear 8 for low speed transmission includes a low speed sun gear 16 as a first component, a planetary carrier 17 as a second component, and an internal gear 18 for low and high speeds as a third component. Consists of. The low-speed sun gear 16 has a front end of a substantially cylindrical member formed as a spline, and the second input gear 15 is externally fitted and fixed. An external gear is formed at the rear end and meshes with the low-speed planetary gear 20, so that the combined output shaft 4 is rotatably fitted through a bearing.
The planetary carrier 17 includes a carrier shaft 17a that integrally supports a planetary gear 20 for low speed and a planetary gear 22 for high speed via a bearing, and one end (rear end) of the carrier shaft 17a. The other end (front end) of the carrier shaft 17a is rotatably supported by a boss portion of the low speed sun gear 16 through a bearing. Further, a rear plate of the low speed clutch boss body 34 of the low speed clutch 11 is fixed to the rear end of the cylindrical body 17b, and an outer peripheral side of the low speed clutch boss body 34 and a low / high speed clutch case 35 are provided. Friction plates are respectively locked inside. The friction plates are alternately arranged to constitute a low speed clutch 11. A low speed clutch 11 and a high speed clutch 12 are included in the cylindrical body 17b, and a low and high speed carrier shaft 17a is projected forward from the front end surface of the cylindrical body 17b. A first reverse carrier shaft 23 and a second reverse carrier shaft 24 project rearward from the rear plate 34.

  The low / high-speed internal gear 18 as the third component meshes with the high-speed planetary gear 22 and is fixed to the transmission gear 19 via a connecting member 33. The transmission gear 19 is rotatably supported by a boss portion of the low speed sun gear 16 via a bearing. The transmission gear 19 meshes with the HST output gear 29. The HST output gear 29 is fixed on the HST output shaft 3.

  Thus, in the low speed transmission mechanism 5, the output from the engine 51 is transmitted from the first input gear 14 on the input shaft 2 to the low speed sun gear 16 of the low speed transmission planetary gear 8 via the second input gear 15. The HST output gear 29 fixed on the HST output shaft 3 is transmitted to the low and high speed internal gear 18 of the low speed transmission planetary gear 8 through the transmission gear 19 and the connecting member 33, and the combination of the two. The transmitted power is transmitted from the carrier shaft 17a to the low-speed clutch boss body 34 of the low-speed clutch 11 through the cylindrical body 17b. That is, the low speed transmission mechanism 5 inputs and synthesizes power from the low speed sun gear 16 as the first component and the low / high speed internal gear 18 as the third component, and shifts the second component. It is configured to output from the planetary carrier 17.

As shown in FIG. 3, the planetary gear 9 for high speed transmission includes a high speed sun gear 21 as a first component, a high speed planetary gear 22 as a second component, and a low and high speed internal gear as a third component. And lugia 18. The high speed sun gear 21 is rotatably supported on the composite output shaft 4 and is integrally fixed to the front end of the high speed clutch boss body 36 constituting the high speed clutch 12. The high speed clutch boss body 36 and the low and high speed clutch case 35 are respectively engaged with friction plates, and the friction plates are alternately arranged to constitute the high speed clutch 12. . The high-speed sun gear 21 meshes with the high-speed planetary gear 22 as a circular external gear.
The high-speed planetary gear 22 is rotatably fitted on the carrier shaft 17 a constituting the planetary carrier 17 and meshed with the low / high-speed internal gear 18.

With the above configuration, the power output from the HST output shaft 3 is transmitted to the high speed transmission mechanism 6 to the low / high speed internal gear 18 via the HST output gear 29, the transmission gear 19, and the connecting member 33. It is done. The power from the HST 52 is transmitted to the high-speed planetary gear 22 via the input shaft 2, the first input gear 14, the second input gear 15, and the low-speed sun gear 16. These two powers are combined and transmitted from the high speed sun gear 21 to the high speed clutch 12. That is, the high speed planetary gear 22 as the second constituent element and the power from the low / high speed internal gear 18 as the third constituent element are input and combined to change the speed, and the high speed sun gear as the first constituent element. 21 is configured to output.
As described above, the planetary carrier 17 is driven to rotate by the action of the relative rotation of the planetary gears 8 for the low speed transmission planetary gear 8 and the high speed transmission planetary gear 9.

  The low speed clutch 11 and the high speed clutch 12 are each constituted by a hydraulic clutch, and the clutch is "on" (contact) by feeding pressure oil and sliding the piston to press the friction plate. It can be. The low / high speed clutch case 35 is fixed on the combined output shaft 4 and transmits power from the rear portion of the combined output shaft 4 to the drive wheels 39 via the auxiliary transmission mechanism 37 and the differential device 38. .

In such a configuration, when the vehicle travels in the low speed mode, that is, with the low speed clutch 11 set to “ON”, the power from the engine 51 is input to the HST 52 from the input shaft 2 to be shifted, and the hydraulic motor 54 The low and high speed internal gear 18 is driven from the HST output shaft 3 through the HST output gear 29, the transmission gear 19, and the connecting member 33.
On the other hand, the low speed sun gear 16 is driven from the input shaft 2 through the first input gear 14 and the second input gear 15. Since the low / high speed internal gear 18 meshes with the high speed planetary gear 22 and the low speed sun gear 16 meshes with the low speed planetary gear 20, the rotation of the low / high speed internal gear 18 and the low speed sun gear 16 rotate. Are combined and output from the planetary carrier 17. In other words, the output rotation of the carrier shaft 17a is transmitted to the composite output shaft 4 through the cylinder body 17b, the low speed clutch boss body 34, and the low speed clutch 11 and is driven through the auxiliary transmission mechanism 37 and the differential device 38 to the drive wheels 39. Is driven at a low speed. The relationship between the rotational speed of the HMT output shaft (synthetic output shaft) 4 and the rotational speed of the HST output shaft 3 at this time is as shown by a diagram L in FIG.

Further, when the vehicle travels in the high speed mode, that is, when the high speed clutch 12 is “on”, the power from the engine 51 is input to the HST 52 from the input shaft 2 to be shifted, and from the HST output shaft 3 of the hydraulic motor 54. Similarly to the above, the low / high speed internal gear 18 is driven through the HST output gear 29, the transmission gear 19, and the connecting member 33.
On the other hand, it is transmitted from the input shaft 2 to the low speed sun gear 16 via the first input gear 14 and the second input gear 15 and further transmitted to the low speed planetary gear 20 to rotate the planetary carrier 17.
Thus, the rotation of the low / high speed internal gear 18 and the rotation of the planetary carrier 17 are combined and output from the high speed sun gear 21, and the high speed clutch boss body 36 passes through the high speed clutch 12 to the combined output shaft 4. Accordingly, the drive wheels 39 are driven at high speed via the auxiliary transmission mechanism 37 and the differential device 38. The relationship between the rotational speed of the HMT output shaft (synthetic output shaft) 4 and the rotational speed of the HST output shaft 3 at this time is as shown by a diagram H in FIG. The number of teeth of each planetary gear is set so that the characteristics of the high speed mode H and the characteristics of the low speed mode L are symmetric at the rotational speed N1. In this way, the shift feeling (acceleration / deceleration) in the low-speed mode and in the high-speed mode becomes substantially the same, and operability can be improved.

Next, details of the reverse transmission mechanism 7 will be described.
As shown in FIGS. 1 to 3, the reverse shifting planetary gear 10 includes a reverse sun gear 28 as a first component, a planetary carrier 17 as a second component, and a reverse internal gear as a third component. 27. The reverse sun gear 28 is formed of a circular external gear. A reverse clutch boss body 32 is fixed to the rear portion of the reverse sun gear 28, and is mounted on the reverse clutch boss body 32 and a reverse clutch case 40 that is externally fitted and fixed on the composite output shaft 4. The friction plates are respectively locked, and the friction plates are alternately arranged. Then, the clutch can be turned “ON” by sliding the piston with pressure oil and pressing the friction plate. Thus, the hydraulic reverse clutch 13 is configured.
The planetary carrier 17 is provided with a first reverse carrier shaft 23 and a second reverse carrier shaft 24 between the low speed clutch boss body 34 and a bearing on the first reverse carrier shaft 23. The first reverse planetary gear 25 is rotatably supported, and the second reverse planetary gear 26 is rotatably supported on the second reverse carrier shaft 24 via a bearing. The reverse internal gear 27 is composed of a ring-shaped internal gear and is fixed to the transmission case 50.
The first reverse planetary gear 25 is meshed with the reverse sun gear 28 and the second reverse planetary gear 26, and the second reverse planetary gear 26 is connected to the first reverse planetary gear 25 and the reverse internal gear 27. Mesh.

  Since the first reverse planetary gear 25 and the second reverse planetary gear 26 mesh with each other, the output rotations of the first reverse planetary gear 25 and the second reverse planetary gear 26 are configured to be opposite to each other. Has been. Therefore, the rotation output transmitted through the planetary carrier 17 is reverse to the rotation direction of the low-speed transmission mechanism 5 and the high-speed transmission mechanism 6 (both for forward movement) and transmitted to the reverse transmission mechanism 7. By doing so, it is possible to move backward (reverse rotation of the composite output shaft 4).

  When the planetary carrier 17 rotates, the reverse internal gear 27 is fixed to the transmission case 50. Therefore, the first reverse carrier shaft 23 and the second reverse carrier shaft 24 that protrude from the planetary carrier 17 are provided. The first reverse planetary gear 25 and the second reverse planetary gear 26 that are externally fitted to each other are rotated (revolved) around the reverse sun gear 28 while rotating in reverse directions (revolving). A rotational output is obtained from the sun gear 28. Then, by setting the reverse clutch 13 to “ON”, the rotation output is transmitted to the composite output shaft 4 and becomes the rotation output in the reverse mode. The relationship between the rotational speed of the HMT output shaft (synthetic output shaft) 4 and the rotational speed of the HST output shaft 3 at this time is as shown by a diagram R in FIG. The number of teeth of each planetary gear is set so that the characteristics of the reverse mode R and the characteristics of the low speed mode L are symmetrical at the rotational speed 0 position. Further, the number of teeth of each planetary gear is set so that the characteristics of the reverse mode R and the characteristics of the high speed mode H are parallel to each other. In this way, substantially the same shifting feeling is obtained in the reverse mode and the low speed mode, and the operability can be improved.

  In this way, it is possible to configure each of the low speed, high speed, and reverse gear modes with a simple configuration in which a hydraulic clutch is arranged at the subsequent stage of the planetary gear mechanism and the hydraulic clutch is switched, and switching between the modes is simple and easy to understand. It becomes.

  The low speed transmission planetary gear 8 and the high speed transmission planetary gear 9 have a common low / high speed carrier shaft 17a. The carrier shaft 17a and the first reverse carrier shaft 23 of the reverse transmission planetary gear 10 and The second reverse carrier shaft 24 is integrally formed through a cylindrical body 17b and a low-speed clutch boss body 34.

  In other words, as shown in FIGS. 1 and 2, the planetary carrier 17 is shared by the planetary gears 8, 9, and 10, and includes a low and high speed carrier shaft 17 a in the front, and a first reverse gear in the rear. The carrier shaft 23 and the second reverse carrier shaft 24 are provided.

  Accordingly, the carrier shafts of the three planetary gears are integrated, and the planetary gears can be arranged close to each other, thereby enabling a compact device configuration.

  The HMT 57 is arranged from the upstream side of the drive with a low speed shifting planetary gear 8, a high speed shifting planetary gear 9, a high speed clutch 12, a low speed clutch 11, a reverse shifting planetary gear 10, and a reverse shifting clutch 13. is there.

  In other words, as shown in FIGS. 1 and 2, the components of each of the speed change mechanisms 5, 6, and 7 are the planetary gear 8 for low speed transmission and the planetary gear for high speed transmission from the front with the combined output shaft 4 as the same axis. 9, the high-speed clutch 12, the low-speed clutch 11, the reverse transmission planetary gear 10, and the reverse clutch 13 are arranged so that their constituent elements are arranged close to each other.

Accordingly, since the planetary gears 8, 9, 10 are decelerated, the axial direction can be shortened, and a compact transmission can be configured.
Further, the clutches 11, 12, and 13 can be arranged side by side in the axial direction, and the configuration of the hydraulic piping can be simplified.

The skeleton figure which showed the drive structure of the working vehicle which concerns on one Example of this invention. Sectional drawing of the mission part which showed the structure of HMT which concerns on one Example of this invention. Similarly, a cross-sectional detail view of the mission part. The correlation diagram which shows the relationship between the rotation speed in the HST motor output shaft and HMT output shaft which concerns on one Example of this invention.

Explanation of symbols

5 Low-speed transmission mechanism 6 High-speed transmission mechanism 7 Reverse transmission mechanism 8 Low-speed transmission planetary gear 9 High-speed transmission planetary gear 10 Reverse transmission planetary gear 11 Low-speed clutch 12 High-speed clutch 13 Reverse-travel clutch 52 HST
57 HMT

Claims (4)

In a hydraulic-mechanical transmission (HMT) installed in a work vehicle that is provided with a hydraulic continuously variable transmission and a planetary gear mechanism at a subsequent stage of a drive source and outputs combined power,
On the same axis, a low-speed transmission mechanism comprising a low-speed transmission planetary gear and a low-speed clutch, a high-speed transmission mechanism comprising a high-speed transmission planetary gear and a high-speed clutch, a reverse transmission planetary gear, and a reverse clutch. A hydraulic-mechanical transmission device mounted on a work vehicle, wherein a reverse transmission mechanism is arranged.   Power from the engine is transmitted to the sun gear of the planetary gear for low speed transmission, power transmitted by a hydraulic continuously variable transmission (HST) is transmitted to the internal gear of the planetary gear for high speed transmission, and each clutch is transmitted from a common carrier to each clutch. The hydraulic-mechanical transmission device mounted on a work vehicle according to claim 1, wherein the structure is configured to transmit power.   The carrier shaft of the planetary gear for low-speed transmission, the carrier shaft of the planetary gear for high-speed transmission, and the carrier shaft of the planetary gear for reverse transmission are integrally configured as claimed in claim 1 or 2. A hydraulic-mechanical transmission installed in the described work vehicle.   The hydraulic-mechanical transmission is characterized in that a low-speed transmission planetary gear, a high-speed transmission planetary gear, a high-speed clutch, a low-speed clutch, a reverse transmission planetary gear, and a reverse clutch are arranged from the upstream side of the drive. A hydraulic-mechanical transmission device installed in a work vehicle according to claim 1.

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