JPH07110023A - Torque shaft receiving radial load - Google Patents

Abstract

PURPOSE:To provide a torque shaft which absorbs a radial load and can transmit drive torque while transmitting no radial load to the drive side. CONSTITUTION:A shaft 3 generating a drive torque while receiving a radial load is constituted of a torque transmitting shaft 16 and a radial load shaft 17 concentrically fitted to the shaft 16. Both shafts are engaged with each other slidably only in the axial direction by spline construction 18 and the like, in addition the torque transmitting shaft 16 is formed with a small diameter part 19, and a gap (s) is formed between the torque transmitting shaft 16 on the drive side of the small diameter part 19 and the inner face of the radial load shaft 17.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque shaft that receives a load in a radial direction while transmitting torque like a shaft for driving a crank arm.

[0002]

2. Description of the Related Art FIG. 4 shows a crank type mold clamping mechanism of an injection molding machine, in which power from a motor M is a rear platen RP.
It is transmitted to the crank arm A via the speed reducer R and the output shaft S attached to the. By the rotation of the crank arm A, the movable side mold MM attached to the movable platen MP is opened and closed and clamped with respect to the fixed side mold SM attached to the fixed platen SP. FIG. 2 shows an example of a speed reducer R used for driving a toggle link of an injection molding machine and driving a robot arm. In the speed reducer 1 (speed reducer R), the high speed rotation transmitted to the input shaft 2 is significantly reduced through the differential gear assembly 4 interposed between the output shaft 3 (output shaft S) and the low speed rotation. Is said to be the rotation of. Reference numeral 5 is a housing, and reference numeral 6 is a bearing that supports the output shaft 3.

In this case, the output shaft 3 is a shaft which generates a driving torque, and when it is used as a driving shaft of a toggle link, for example, it may receive a radial load (F) during operation. In the speed reducer 1 fixed at a fixed position, the radial load acts so as to displace or bend the coincident shaft centers of the input shaft 2 and the output shaft 3. May be damaged. The influence of such a radial load becomes more remarkable as the configuration provided on the drive side of the torque shaft is more precise (for example, a precision reducer).

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a torque shaft capable of transmitting a driving torque while absorbing a radial load and not transmitting it to the drive side.

[0005]

A shaft for generating a driving torque while receiving a radial load is composed of a torque transmission shaft and a radial load shaft fitted coaxially therewith. At the fitting points of both shafts, both shafts are fitted so as to be slidable only in the axial direction, and a small diameter portion having a reduced diameter is formed on the torque transmission shaft. A gap is formed between the torque transmission shaft on the drive side of the small diameter portion and the inner surface of the radial load shaft.

[0006]

The structure in which the torque transmission shaft and the radial load shaft are slidably fitted only in the axial direction enables transmission of torque. The structure in which a gap is formed between the small diameter part formed on the torque transmission shaft and the inner surface of the torque transmission shaft and the radial load shaft on the drive side from this part prevents the shaft bending due to the radial load from being transmitted to the drive side. To do.

[0007]

1 shows a speed reducer 1 in an injection molding machine, which is fixed to a rear platen by a housing 5. Inside the housing 5, the input shaft 2 and the output shaft 3 are connected via a stored differential gear assembly 4.

The differential gear assembly 4 has a structure in which a planetary gear mechanism 9 is revolved along the inner teeth 7 together with the rotation of a planet gear 10 in a casing 8 (FIG. 3) having inner teeth 7 on the inner wall. It is equipped and commercially available. A pinion fixed to the front end of the input shaft 2 meshes with the planetary gear 10 as a sun gear 11 to rotate the planetary gear 10, and also the machine frame 1 of the planetary gear mechanism 9.
2 is connected to the output shaft 3 so that a large gear ratio can be obtained. In addition, the input shaft 2 and the output shaft 3 are arranged exactly on the same axis.

The input shaft 2 is rotatably supported by a bearing 13 on the rear surface side of the housing 5, and is connected to the differential gear assembly 4 by a sun gear 11 fixed to the front end portion.
Further, a toothed pulley 14 is fixed to the rear end portion, and is linked with a mold clamping motor (not shown) output shaft by a timing belt 15.

The output shaft 3 comprises a torque transmission shaft 16 and a radial load shaft 17 fitted coaxially with the torque transmission shaft 16. These shafts have spline structure 1 at the mating point.
8 is slidably fitted only in the axial direction, and a small diameter portion 19 having a reduced diameter is formed on the torque transmission shaft. The torque transmission shaft 16 on the drive side of the small diameter portion 19 and the inner surface of the radial load shaft 17 are connected to each other. A gap (s) is formed between them. The base of the crank arm is fixed to the radial load shaft 17 of the output shaft 3.

In the mold clamping process of the injection molding cycle, the power from the mold clamping motor is transmitted to the input shaft 2 via the timing belt 15 and the toothed pulley 14. The high-speed rotation of the input shaft 2 is decelerated by the differential gear assembly 4, and the torque transmission shaft 16 extracts the power of a predetermined rotation speed and a predetermined torque. The crank arm connected to the radial load shaft 17 of the output shaft 3 is driven and rotated by this rotational speed and torque via the spline structure 18 to generate a mold clamping force. At that time,
The radial load shaft 17 may receive a radial load in a direction perpendicular to the axial direction.

At this time, the radial load is transmitted to the torque transmission shaft 16 via the radial load shaft 17 and acts to displace or bend the torque transmission shaft 16. However, the radial load shaft 17 and the torque transmission shaft 16 can be slid in the axial direction by the spline structure 18, the gap (s) is formed, and the small diameter portion 19 is formed on the torque transmission shaft 16, so that the radial load is If so, the radial load shaft 17 slides with respect to the torque transmission shaft 16, and the torque transmission shaft 16 bends at the small diameter portion 19 to absorb the radial load. Therefore, the radial load hardly influences the fixed portion between the torque transmission shaft 16 and the differential gear assembly 4, and the uneven distribution of the force does not occur in the differential gear assembly 4. Therefore,
The differential gear assembly 4 is free from damage such as missing gear teeth and uneven wear.

The above is an embodiment, and the present invention is not limited to the illustrated specific configuration. INDUSTRIAL APPLICABILITY The present invention can be applied not only to the speed reducer 1 of an injection molding machine but also to a speed reducer in general, and not only to the output shaft 3 of the speed reducer 1, but to a torque shaft in general that receives a radial load.

[0014]

EFFECTS OF THE INVENTION In a torque shaft that receives a radial load, the displacement or bending of the shaft due to the radial load hardly reaches the drive side, and damage to the drive side device such as a reduction gear is prevented.

[Brief description of drawings]

FIG. 1 is a front view showing a cross section of a speed reducer (embodiment).

FIG. 2 is a front view showing a cross section of a speed reducer (conventional example).

FIG. 3 is a schematic diagram of a speed reducer schematically shown.

FIG. 4 is a mechanism diagram of a mold clamping device.

[Explanation of symbols]

 1 reducer 2 input shaft 3 output shaft 4 differential gear assembly 5 housing 6 bearing 7 internal teeth 8 casing 9 planetary gear mechanism 10 planetary gear 11 sun gear 12 machine frame 13 bearing 14 toothed pulley 15 timing belt 16 torque transmission shaft 17 Radial load shaft 18 Spline structure 19 Small diameter part

Claims (1)

[Claims] 1. A shaft for generating a driving torque while receiving a radial load, comprising a torque transmission shaft and a radial load shaft fitted coaxially with the shaft, and at the fitting points of both shafts, both shafts are It is fitted so that it can slide only in the axial direction, and a small diameter part with a smaller diameter is formed on the torque transmission shaft, and a gap is formed between the torque transmission shaft on the drive side of the small diameter part and the inner surface of the radial load shaft. A torque shaft that receives a radial load.