JP2014066332A - Auxiliary transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an auxiliary transmission from being in a neutral state to prevent a vehicle from moving on a slope road or the like against the intention of a driver.SOLUTION: On the assumption that a slow speed stage is formed by moving a gear part 23 of a sleeve 7 in one axial direction and engaging the gear part 23 with a low speed gear 24 and a high speed stage is formed by moving the gear part 23 of the sleeve 7 in the other axial direction and engaging the gear part 23 with a high speed gear 25, the width dimension of the gear part 23 of the sleeve 7 is set so as to engage the gear part 23 with one of the low speed gear 24 and the high speed gear 25.

Description

  The present invention relates to an auxiliary transmission mounted on a vehicle together with a main transmission.

  Patent Document 1 discloses a shift control device including a sub-transmission. In this auxiliary transmission, a sleeve (switching sleeve) in which inner teeth and outer teeth are formed on both sides in the axial direction is slid in one axial direction so that the inner teeth mesh with the high speed gear to form a high speed stage. On the other hand, by sliding the sleeve in the other axial direction, the external teeth mesh with the low speed gear to form a low speed stage. In this shift control device, the vehicle is prevented from moving backward when starting uphill by predetermined control.

  Patent Document 2 discloses a synchro mechanism for an auxiliary transmission. In this synchronizer mechanism, the sleeve is formed wide so that the sleeve always meshes with at least one of the low speed side synchronizer ring and the high speed side synchronizer ring. By widening the sleeve, the amount of engagement between the inner teeth of the sleeve and the outer teeth of the synchronizer hub is increased, and the shift stroke amount (the amount of movement of the sleeve) is decreased. As a result, gear loss is prevented and shift operation force is reduced.

JP 2008-190646 A Japanese Patent Publication No. 61-40858

  However, in the auxiliary transmission disclosed in Patent Document 1, when the sleeve is in the intermediate position, a neutral state that does not mesh with either the high speed gear or the low speed gear is formed, so the vehicle starts on a slope or the like. At this time, if the sub-transmission is in a neutral state and the driver does not step on the brake, the vehicle may move backward against the driver's will.

  Further, in the auxiliary transmission disclosed in Patent Document 2, the sleeve meshes with at least one of the low speed side synchronizer ring and the high speed side synchronizer ring, but the sleeve meshes with either the high speed gear or the low speed gear. If the driver does not step on the brake when starting the vehicle on a slope or the like, as in the case of the sub-transmission of Patent Document 1, the vehicle is contrary to the driver's will. May fall back.

  The present invention has been made in view of such problems, and prevents the auxiliary transmission from entering a neutral state and prevents the vehicle from moving against a driver's intention on a slope or the like. An object is to provide an auxiliary transmission.

  The auxiliary transmission of the present invention forms a low speed stage by moving the gear portion of the sleeve in one axial direction and meshing with the low speed gear, and moves the gear portion of the sleeve in the other axial direction and meshing with the high speed gear. It is premised on what forms a high-speed stage, and the width of the gear portion of the sleeve is set so as to mesh with at least one of the low-speed gear and the high-speed gear. It is said.

  According to the sub-transmission having such a configuration, since the gear portion of the sleeve meshes with at least one of the low speed gear and the high speed gear, a neutral state is not formed. This prevents the vehicle from moving against the driver's will even if the brake is not depressed on a hill or the like.

  According to the present invention, it is possible to prevent the vehicle from moving against the driver's will even if the brake is not depressed on a slope.

It is sectional drawing which shows the principal part of the auxiliary transmission which concerns on embodiment of this invention, its peripheral part, etc. FIG.

  Hereinafter, an auxiliary transmission according to an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, an explanation will be given by taking as an example a sub-transmission mounted on a part-time 4WD vehicle that can switch between 2WD and 4WD. Of course, the vehicle which can apply the auxiliary transmission of this invention is not limited to this.

  FIG. 1 shows a main part of the auxiliary transmission 1 and its surroundings. The auxiliary transmission 1 is mainly composed of a low speed gear member 6, a sleeve 7, a high speed gear member 8, a sleeve engaging tooth 27, and the like.

  Reference numeral 2 denotes a first gear to which the rotational power of the engine is transmitted via the main transmission. The first gear includes a gear portion 11 formed of a spur gear, a helical gear, and the like, and a shaft portion 12. The shaft portion 12 is rotatably supported in a transfer case 14 via a bearing 13. ing. A male spline tooth 29 is formed at the tip of the shaft portion 12.

  Reference numeral 3 denotes a second gear having a gear portion 16 meshed with the gear portion 11 of the first gear 2. The second gear 3 also has a shaft portion 17 that is rotatably supported in the transfer case 14 via a bearing 18. Male spline teeth 20 are formed at the end of the shaft portion 17, and the male spline teeth 20 are spline-fitted with female spline teeth 30 formed in the counter shaft 4 described later.

  4 is a countershaft. The counter shaft 4 is rotatably supported in the transfer case 14 via a bearing 19 and is disposed substantially parallel to an output shaft 9 described later. The counter shaft 4 is provided with a gear portion 22 formed of a spur gear, a helical gear, or the like, and the gear portion 22 meshes with a gear portion 21 of a low-speed gear member 6 described later.

  The low speed gear member 6 includes the gear portion 21 and a low speed gear 24 that meshes with an inner tooth 23 of a sleeve 7 to be described later. The low speed gear member 6 is fitted on the outer periphery of the output shaft 9 through a needle bearing 26 and the like so as to be relatively rotatable.

  The sleeve 7 has the inner teeth 23, and an engagement groove 7a in the circumferential direction in which a shift fork (not shown) is engaged is formed on the outer peripheral portion. The inner teeth 23 of the sleeve 7 mesh with sleeve engaging teeth 27 formed on the outer periphery of one end of the output shaft 9 so as to be slidable in the axial direction. The sleeve 7 moves in one axial direction, so that its internal teeth 23 mesh with the low speed gear 24 and transmit power between the low speed gear member 6 and the output shaft 9 (that is, a low speed stage is formed). ). Further, when the sleeve 7 moves to the other in the axial direction, its internal teeth 23 mesh with a high speed gear 25 described later, and power is transmitted between the high speed gear member 8 and the output shaft 9 (that is, the high speed stage). Form). In the present embodiment, the width dimension of the internal tooth 23 of the sleeve 7 is set so that it always meshes with at least one of the low speed gear 24 and the high speed gear 25. For this reason, in the example shown in FIG. 1, the width dimension of the sleeve 7 is set larger than the axial distance between the low speed gear 24 and the high speed gear 25. In the auxiliary transmission 1 according to the present embodiment, it is necessary to change gears (switch between the low speed stage and the high speed stage) while the vehicle is stopped.

  The high-speed gear member 8 has female spline teeth 28 in its shaft hole, and the spline teeth 28 are spline-fitted with male spline teeth 29 formed at the tip of the shaft portion 12 of the first gear 2. Yes. That is, the high speed gear member 8 always rotates integrally with the first gear 2.

  The output shaft 9 is rotatably supported in the transfer case 14 by bearings 34 and 35, and further, one end side of the output shaft 9 rotates integrally with the sleeve 7 slidably engaged in the axial direction as described above. It has become. Further, the other end side of the output shaft 9 is spline-fitted with a joint member 31 with a propeller shaft (not shown), and a middle part of the output shaft 9 is one component (boss portion) of the 2WD / 4WD switching mechanism 32 33) and spline fitting. When the 2WD / 4WD switching mechanism 32 is switched to 2WD, the power input to the output shaft 9 is transmitted only to the rear wheel side (joint member 31), and when the 2WD / 4WD switching mechanism 32 is switched to 4WD, the output is output. The power input to the shaft 9 is transmitted not only to the rear wheel side but also to the front wheel side via the front drive chain 36 and the like.

  Reference numeral 37 denotes an actuator that switches the sub-transmission 1 between a low speed stage and a high speed stage in accordance with a drive command from the transmission ECU 38. The actuator 37 is connected to a shift fork (not shown) engaged with the engagement groove 7a of the sleeve 7 via a predetermined mechanism, and can move the sleeve 7 in one axial direction or the other axial direction. it can.

  In the present embodiment, a drive command is input from the transmission ECU 38 to the actuator 37 by inputting a switching signal to the transmission ECU 38 by an operation of a predetermined sub-transmission switching operation unit 39 installed in the driver's seat. Then, according to the drive command, the actuator 37 moves the sleeve 7 in one axial direction or the other axial direction to switch between the low speed stage and the high speed stage.

  In addition, the auxiliary transmission 1 is automatically switched to a high speed stage or a low speed stage depending on the loading amount (loading weight) of the vehicle. In other words, a load detection sensor 40 is installed in the vehicle on which the auxiliary transmission 1 is mounted, and the transmission ECU 38 drives the actuator 37 based on the output signal of the load detection sensor 40. Then, the sleeve 7 is moved in one axial direction or the other axial direction to switch to the low speed stage or the high speed stage. For example, when the sub-transmission 1 is in a high-speed state, when the output signal of the load detection sensor 40 is a signal level that is output when the load of the vehicle is greater than or equal to a predetermined value, the transmission ECU 38 Drives the actuator 37 to move the sleeve 7 in one axial direction to switch from the high speed stage to the low speed stage. Conversely, when the sub-transmission 1 is in the low speed stage and the output signal of the load detection sensor 40 has a signal level that is output when the load of the vehicle is less than a predetermined value, the transmission ECU 38 The actuator 37 is driven to move the sleeve 7 in the other axial direction to switch from the low speed stage to the high speed stage.

  As the load amount detection sensor 40, for example, a sensor for detecting the amount of vehicle inclination can be used or combined to correct the optical axis of the headlamp. For example, when the amount of vehicle inclination is equal to or greater than a predetermined angle obliquely upward toward the front, it is considered that the load amount is equal to or greater than a predetermined value, and the amount of vehicle inclination is less than the predetermined angle obliquely upward toward the front By assuming that the load amount is less than the predetermined value, the inclination amount detection sensor can be used as the load amount detection sensor 40.

  As is clear from the above description, according to the auxiliary transmission 1 according to the embodiment of the present invention, the internal teeth 23 (gear portion) of the sleeve 7 are connected to at least one of the low speed gear 24 and the high speed gear 25. Since the width dimension is set so as to engage with each other and a neutral state is not formed, the vehicle is prevented from retreating against the intention of the driver even if the brake is not stepped on a slope or the like. .

  Note that the present invention is not limited to the type of sub-transmission that automatically shifts as described above, but can also be applied to a type of sub-transmission that manually shifts. However, in the case of a vehicle equipped with a sub-transmission that automatically shifts, the driver often forgets to step on the brake on a slope or the like, so the sub-transmission that automatically shifts is more suitable for the present invention. Opportunities to enjoy the effect increase.

  The present invention can be applied to a vehicular auxiliary transmission that shifts automatically or manually.

1 Sub-transmission 7 Sleeve 23 Internal teeth of the sleeve (gear part)
24 Low speed gear 25 High speed gear

Claims (1)

The gear portion of the sleeve is moved in one axial direction and meshed with the low speed gear to form a low speed stage, and the sleeve gear portion is moved in the other axial direction and meshed with the high speed gear to form the high speed stage. In the transmission,
The sub-transmission is characterized in that the width of the gear portion of the sleeve is set so as to mesh with at least one of the low-speed gear and the high-speed gear.

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