Ball screw device test equipment

Abstract

The ball screw device testing device includes a support portion that rotatably supports a first rotating component of a ball screw device to be tested and linearly supports a first linear component, a first motor that is disposed in a first direction as viewed from the support portion and generates a torque that rotates the first rotating component, and a load device that is disposed in a second direction as viewed from the support portion and abuts against the first linear component to apply an axial load to the first linear component. The load device includes a second motor, a load-side ball screw device that has a second rotating component that rotates due to the torque generated by the second motor and a second linear component that linearly moves, and an elastic body interposed between the first linear component and the second linear component. The positions of the output shafts of the first motor and the second motor are controllable.

Description

[Technical Field]

[0001] The present disclosure relates to a testing device for a ball screw device. [Background technology]

[0002] A ball screw device is a device that converts rotational motion into linear motion and linear motion into rotational motion. Test devices for ball screw devices have been used to check the operation of ball screw devices and evaluate their efficiency. Examples of test devices for ball screw devices include those disclosed in the following patent documents. Hereinafter, test devices for ball screw devices may be simply referred to as test devices.

[0003] The testing device in the following patent document includes a load device that applies an axial load (hereinafter referred to as an axial load) to a ball screw device. The load device includes a motor and a load-side ball screw device that converts the torque generated by the motor into an axial load. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-294581 [Patent Document 2] Patent No. 7572899 Summary of the Invention [Problem to be solved by the invention]

[0005] According to the above-described test device, the axial load is increased or decreased by controlling the torque of the motor of the load device. While it is possible to control the torque at a constant level with an inexpensive motor, an expensive motor is used to achieve arbitrary torque control. In recent years, there has been a demand for test devices that use inexpensive motors that can control the position of the output shaft, rather than expensive motors that can control arbitrary torque. There is also a demand for the ability to adjust the axial load in accordance with the stroke of the ball screw device being tested.

[0006] The present disclosure has been made in consideration of the above, and aims to provide a testing device for a ball screw device that uses a motor that can control the position of the output shaft and can adjust the axial load in accordance with the stroke of the ball screw device. [Means for solving the problem]

[0007] To achieve the above object, a testing device for a ball screw device according to one aspect of the present disclosure includes: a support portion that rotatably supports a first rotating component, either a screw shaft or a nut, of a ball screw device to be tested, and linearly supports a first linear component, the other of the screw shaft and nut; a first motor that is disposed in a first axial direction parallel to the central axis of the screw shaft as viewed from the support portion and generates torque to rotate the first rotating component; and a load device that is disposed in a second axial direction parallel to the other axial direction as viewed from the support portion and abuts against the first linear component to apply an axial load to the first linear component. The load device includes a second motor, a load-side ball screw device having a second rotating component that rotates due to the torque generated by the second motor, and a second linear component that linearly moves due to the rotation of the second rotating component, and an elastic body interposed between the first linear component and the second linear component. The positions of the output shafts of the first motor and the second motor are controllable.

[0008] The present disclosure can control the positions (rotation angles) of the output shafts of the first motor and the second motor. Therefore, the distance between the first linear motion component and the second linear motion component can be adjusted to change the amount of contraction of the elastic body. Furthermore, by changing the amount of contraction of the elastic body, the axial load acting on the first linear motion component can be adjusted to a desired magnitude. Therefore, the present disclosure eliminates the need for a motor to control the axial load (control torque). Furthermore, the present disclosure can change the distance between the first linear motion component and the second linear motion component (the amount of contraction of the elastic body) by driving the second motor, regardless of the axial position of the first linear motion component. Therefore, the axial load can be adjusted (changed) in accordance with the stroke of the ball screw device.

[0009] In the ball screw device testing device, the load device may have a moving part that is arranged movably in the axial direction and abuts against the first linear motion part from the second direction, and the moving part may be biased in the first direction by the elastic body.

[0010] In the above-described ball screw device testing device, the load device has a linear guide that supports the moving part so that the moving part can move in the axial direction.

[0011] According to the above configuration, the moving parts are less likely to rattle.

[0012] Furthermore, in the above-described ball screw device testing device, the loading device has an elastic body support part that supports the elastic body. The elastic body support part has a main body part that is connected to the second linear motion component, and a rod that is movably supported by the main body part and has a flange formed on an end part in the first direction. The rod may pass through the elastic body, and the main body part and the flange may sandwich the elastic body in the axial direction.

[0013] The ball screw device testing device also includes a control unit that controls the driving of the first motor and the second motor. The control unit controls the driving of the first motor so that the first linear moving component moves in the axial direction at a constant speed. The control unit controls the driving of the second motor so that the second linear moving component moves at the same moving speed and in the same direction as the first linear moving component.

[0014] According to the above configuration, the distance between the first linear motion component and the second linear motion component is constant, and the amount of contraction of the elastic body is also constant, so that the axial load remains constant even if the stroke of the ball screw device increases or decreases.

[0015] The ball screw device testing device also includes a control unit that controls the driving of the first motor and the second motor. The control unit controls the driving of the first motor so that the first linear moving component moves in the axial direction at a constant speed. The control unit controls the driving of the second motor so that the second linear moving component moves at a constant speed, and in the same direction as the first linear moving component, but at a moving speed slower than that of the first linear moving component.

[0016] According to the above configuration, when the first linear moving component moves in the second direction, the gap between the first linear moving component and the second linear moving component decreases. Furthermore, because the speeds of the first linear moving component and the second linear moving component are constant, the ratio (proportion) between the amount of movement in the second direction by the first linear moving component and the amount of reduction in the gap between the first linear moving component and the second linear moving component (the amount of contraction of the elastic body) is constant. Therefore, as the amount of movement in the second direction by the first linear moving component increases, the axial load increases linearly.

[0017] The ball screw device testing device also includes a control unit that controls the driving of the first motor and the second motor. The control unit controls the driving of the first motor so that the first linear motion component moves in the axial direction at a constant speed. The control unit controls the driving of the second motor so that the second linear motion component moves in the opposite direction to the first linear motion component at a constant speed.

[0018] According to the above configuration, when the first linear component moves in the second direction, the second linear component moves in the first direction, reducing the gap between the first and second linear components. Furthermore, because the speeds of the first and second linear components are constant, the ratio between the amount of movement of the first linear component in the second direction and the reduction in the gap between the first and second linear components (the contraction amount of the elastic body) is constant. Therefore, as the amount of movement of the first linear component in the second direction increases, the axial load increases linearly.

[0019] The ball screw device testing device also includes a control unit that controls the driving of the first motor and the second motor. The control unit controls the driving of the first motor so that the first linear moving component moves in the axial direction at a constant speed. The control unit controls the driving of the second motor so that the second linear moving component moves in the same direction as the first linear moving component but at a slower moving speed than the first linear moving component. Furthermore, the second linear moving component decelerates as the amount of movement in the second direction increases.

[0020] According to the above configuration, when the first linear moving component moves in the second direction, the distance between the first linear moving component and the second linear moving component decreases. However, the second linear moving component decelerates as the amount of movement in the second direction increases. Therefore, the ratio (proportion) between the amount of movement in the second direction by the first linear moving component and the amount of reduction in the distance between the first linear moving component and the second linear moving component (the amount of contraction of the elastic body) is not constant. According to this driving method, when the amount of movement in the second direction by the first linear moving component increases, the axial load increases. However, when the distance of movement in the second direction of the first linear moving component is small, the axial load is kept small. [Effects of the Invention]

[0021] The ball screw device testing device of the present disclosure does not require an expensive motor for realizing arbitrary torque control to control the axial load, and can adjust the axial load in accordance with the stroke of the ball screw device using an inexpensive motor. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a schematic diagram of a ball screw device testing device according to an embodiment, viewed from a horizontal direction. [Figure 2] FIG. 2 is a graph showing the positions of the first linear moving component and the second linear moving component when the first driving method is performed in the embodiment. [Figure 3] FIG. 3 is a graph showing the relationship between the stroke and the axial load of the ball screw device when the first driving method is implemented in the embodiment. [Figure 4] FIG. 4 is a graph showing the positions of the first linear moving component and the second linear moving component when the second driving method, the third driving method, and the fourth driving method are performed in the embodiment. [Figure 5] FIG. 5 is a graph showing the relationship between the stroke and the axial load of the ball screw device when the second, third, and fourth driving methods are implemented in the embodiment. [Figure 6] FIG. 6 is a graph showing the positions of the first linear moving component and the second linear moving component when the fifth driving method is performed in the embodiment. [Figure 7] FIG. 7 is a graph showing the relationship between the stroke and the axial load of the ball screw device when the fifth driving method is implemented in the embodiment. [Figure 8] FIG. 8 is a schematic diagram of a modified ball screw device testing device viewed from the horizontal direction. DETAILED DESCRIPTION OF THE INVENTION

[0023] The embodiments of the present disclosure will be described in detail with reference to the drawings. The present disclosure is not limited to the contents described below. Furthermore, the components described below include those that can be easily imagined by a person skilled in the art and those that are substantially the same. Furthermore, the components described below can be combined as appropriate.

[0024] (Embodiment) 1 is a schematic diagram of a ball screw device testing device according to an embodiment, viewed from a horizontal direction. Before describing the ball screw device testing device 100 according to an embodiment, a ball screw device 110 will be briefly described. The ball screw device 110 includes a screw shaft 111, a nut 112 into which the screw shaft 111 is inserted, and a plurality of balls (not shown) arranged between the screw shaft 111 and the nut 112. Hereinafter, the direction parallel to the central axis O of the screw shaft 111 will be referred to as the axial direction.

[0025] In a test (hereinafter simply referred to as "test") of the ball screw device test device 100, torque is transmitted to one of the screw shaft 111 and the nut 112, causing the one component (first rotating component) to rotate. The other component (first linear motion component) of the screw shaft 111 and the nut 112 moves linearly in the axial direction (hereinafter may be referred to as linear motion). In this embodiment, the screw shaft 111 corresponds to the first rotating component, and the nut 112 corresponds to the first linear motion component.

[0026] Next, a description will be given of the ball screw device testing device 100. In the following description, a state will be described in which the ball screw device 110 to be tested has already been attached to the ball screw device testing device 100.

[0027] As shown in Figure 1, the embodiment of the testing device 100 for a ball screw device includes a base 101, a support unit 1 that supports the ball screw device 110, an actuation device 2 that operates the ball screw device 110, a load device 3 that applies an axial load to the ball screw device 110, and a control unit 4.

[0028] The base 101 in this embodiment extends in the horizontal direction. The installation surface 102 of the base 101 faces vertically upward in the Y direction. Note that, although the base 101 is horizontal in this embodiment, the present disclosure does not particularly care about the orientation of the base 101, and the base 101 may be inclined with respect to the horizontal direction or the normal to the base 101 may extend in the horizontal direction.

[0029] The support part 1 rotatably supports the screw shaft 111. The support part 1 supports the nut 112 non-rotatably but axially movably. In addition, the ball screw device 110 supported by the support part 1 has the central axis O of the screw shaft 111 horizontal.

[0030] The actuator 2 is disposed on one side of the axial direction as viewed from the support part 1, and the load device 3 is disposed on the other side of the axial direction. Hereinafter, the axial direction in which the actuator 2 is disposed as viewed from the support part 1 will be referred to as the first direction X1, and the axial direction in which the load device 3 is disposed as viewed from the support part 1 will be referred to as the second direction X2.

[0031] The actuation device 2 includes a first motor 20 and a torque sensor 23 arranged in this order from the first direction X1. The first motor 20 generates torque for actuating the ball screw device 110. The first motor 20 is a servo motor including a motor body 21, an output shaft 22 extending from the motor body 21 in the second direction X2, an encoder (not shown) that detects the position (rotation angle) of the output shaft 22, and an amplifier (not shown) that controls the rotation angle of the output shaft 22 to an angle specified by the control unit 4.

[0032] The torque sensor 23 is disposed between the support unit 1 (ball screw device 110) and the first motor 20, and measures the torque transmitted to the ball screw device 110. The torque sensor 23 has a sensor main body 24, a first shaft 25 extending from the sensor main body 24 in a first direction X1, and a second shaft 26 extending from the sensor main body 24 in a second direction X2. The output shaft 22 and the first shaft 25 are connected by a coupling 90. The second shaft 26 and the screw shaft 111 are connected by a coupling 91.

[0033] According to the above-described actuation device 2, when the first motor 20 is driven, torque is transmitted to the screw shaft 111 via the torque sensor 23. Then, the screw shaft 111 rotates, and the nut 112 moves in the axial direction.

[0034] The load device 3 includes a second motor 30, a load side ball screw device 33, an elastic body support portion 37, an elastic body 45, a load cell 47, and a moving part 50 arranged in this order from the second direction X2.

[0035] The second motor 30 generates torque for operating the load-side ball screw device 33. The second motor 30 is a servo motor including a motor body 31, an output shaft 32 extending from the motor body 31 in the first direction X1, an encoder (not shown) that detects the position (rotation angle) of the output shaft 32, and an amplifier (not shown) that controls the rotation angle of the output shaft 32 to an angle specified by the control unit 4.

[0036] The load side ball screw device 33 converts the rotational motion generated by the second motor 30 into linear motion. The load side ball screw device 33 includes a screw shaft 34, a nut 35, and a plurality of balls (not shown). In the load device 3, torque is transmitted to one of the screw shaft 34 and the nut 35, causing the one component (second rotating component) to rotate. The other component (second linear component) of the screw shaft 34 and the nut 35 moves linearly in the axial direction. In the ball screw device testing device 100 of the embodiment, the screw shaft 34 corresponds to the second rotating component, and the nut 35 corresponds to the second linear component.

[0037] The base 101 is provided with a load-side support portion 36 that supports the load-side ball screw device 33. The load-side support portion 36 rotatably supports the screw shaft 34. The load-side support portion 36 supports the nut 35 so that it cannot rotate but can move axially. The screw shaft 34 is connected to the output shaft 32 of the second motor 30 by a coupling 92.

[0038] The elastic body support part 37 includes a main body part 38 and a rod 39 extending from the main body part 38 in the first direction X1. The rod 39 is supported by the main body part 38 so as to be freely movable in the axial direction. Therefore, the elastic body support part 37 is freely expandable and contractible in the axial direction. A flange 40 is provided at the end of the rod 39 in the first direction X1.

[0039] The elastic body 45 is a component that exerts a biasing force. The elastic body 45 is disposed between the end face of the main body 38 in the first direction X1 and the flange 40, and biases the flange 40 in the first direction X1. Specific examples of the elastic body 45 include a coil spring and a disc spring. In addition, in the present disclosure, when a disc spring is used, multiple disc springs may be arranged in the axial direction.

[0040] The main body 38 of this embodiment is supported by a linear guide 41 fixed to a base 101 so as to be freely movable in the axial direction. The linear guide 41 has a rail 42 extending in the axial direction and a slider 43 that is movable in the axial direction along the rail 42. A nut 35 (second linear motion component) of the load-side ball screw device 33 is connected to the end of the main body 38 in the second direction X2.

[0041] The load cell 47 measures the load in the axial direction and is connected to the flange 40 of the elastic support portion 37 in the first direction X1.

[0042] The moving part 50 is connected to the load cell 47 in the first direction X1. A nut 112 of the ball screw device 110 is arranged on the first direction X1 side of the moving part 50. The end of the moving part 50 in the first direction X1 abuts against the surface of the nut 112 in the second direction X2. In addition, a fitting portion 56 recessed in the second direction X2 is formed on the end face 55. The end of the nut 112 in the second direction X2 is fitted into the fitting portion 56.

[0043] The moving part 50 is supported by a linear guide 51 fixed to a base 101 so as to be movable in the axial direction. The linear guide 51 has a rail 52 extending in the axial direction and a slider 53 which is movable in the axial direction along the rail 52. In addition, a preload is applied to the linear guide 51 of this embodiment, so that the moving part 50 is less likely to rattle.

[0044] According to the above-described loading device 3, when the distance between the nut 112 (first linear motion component) and the nut 35 (second linear motion component) becomes smaller, the axial length L1 (see FIG. 1) of the elastic body 45 becomes smaller. Furthermore, when the axial length L1 of the elastic body 45 becomes shorter than the natural length of the elastic body 45, the elastic body 45 accumulates elastic energy. As a result, the elastic body 45 biases the moving component 50 in the first direction X1. Then, the moving component 50 presses the nut 112 in the first direction X1 (see arrow A in FIG. 1). In this way, a load (axial load) in the first direction X1 acts on the nut 112.

[0045] The control unit 4 is a device for controlling the driving of the first motor 20 and the second motor 30. The control unit 4 controls the operation of the ball screw device 110 through control of the first motor 20. In other words, the control unit 4 controls the position (rotation angle) of the output shaft 22 of the first motor 20 so that the ball screw device 110 performs an operation corresponding to the test content.

[0046] Furthermore, the control unit 4 controls the axial position of the nut 35 (the distance from the nut 35 to the nut 112) via the drive of the second motor 30. Here, as the distance between the nut 35 and the nut 112 increases, the amount of contraction of the elastic body 45 decreases, and the axial load becomes smaller. On the other hand, as the distance between the nut 35 and the nut 112 decreases, the amount of contraction of the elastic body 45 increases, and the axial load becomes larger. In this way, the magnitude of the axial load is determined by the distance between the nut 112 and the nut 35. From the above, the control unit 4 controls the position (rotation angle) of the output shaft 32 of the second motor 30, so that the axial load becomes a predetermined magnitude.

[0047] Next, the drive methods of the first motor 20 and the second motor 30 during testing will be described. In this embodiment, one drive method for the first motor 20 will be exemplified. On the other hand, there are five drive methods for the second motor 30 (first drive method, second drive method, third drive method, fourth drive method, and fifth drive method). Each drive method will be described below.

[0048] (First motor driving method) FIG. 2 is a graph showing the positions of the first linear motion component and the second linear motion component when the first driving method is implemented in the embodiment. The driving method of the first motor 20 involves repeatedly rotating the output shaft 22 of the first motor 20 in the forward direction and then in the reverse direction. As a result, as shown in FIG. 2, the nut 112 (first linear motion component) of the ball screw device 110 moves from the initial position in the second direction X2, then moves in the first direction X1, and returns to the initial position, repeating this operation. The moving speed of the nut 112 is set to be constant. Furthermore, this driving method of the first motor 20 is consistent with each driving method of the second motor 30.

[0049] (First driving method of second motor) In the first driving method of the second motor 30, the second motor 30 is driven before the start of the test to make the length L1 of the elastic body 45 shorter than its natural length. This causes the elastic body 45 to contract, and a predetermined amount of axial load is applied to the nut 112 from the start of the test.

[0050] When the test starts, the output shaft 32 of the second motor 30 is rotated forward and then reversely, and this operation is repeated. In other words, the nut 35 (second linear motion component) moves in the same direction as the nut 112 of the ball screw device 110. The moving speed of the nut 35 is set to the same speed as the nut 112. According to this first driving method, the distance between the nut 112 and the nut 35 is always constant. In other words, the contraction amount of the elastic body 45 is constant, and the axial load is also constant.

[0051] Fig. 3 is a graph showing the relationship between the stroke of the ball screw device and the axial load when the first driving method is implemented in the embodiment. Note that the stroke on the horizontal axis in Fig. 3 indicates the amount of movement of the nut 112 (first linear moving component) from its initial position in the second direction X2. As shown in Fig. 3, according to the first driving method, even if the stroke of the ball screw device 110 changes (even if the axial position of the nut 112 changes), the axial load acting on the nut 112 remains constant.

[0052] Next, the second to fourth drive methods will be described. Here, in the second to fourth drive methods, the second motor 30 is not driven before the start of the test. In other words, the length L1 of the elastic body 45 is the natural length of the elastic body 45, and no axial load is applied to the ball screw device 110 at the start of the test.

[0053] (Second driving method of second motor) Fig. 4 is a graph showing the positions of the first linear motion component and the second linear motion component when the second, third, and fourth driving methods are implemented in the embodiment. Fig. 5 is a graph showing the relationship between the stroke and the axial load of the ball screw device when the second, third, and fourth driving methods are implemented in the embodiment.

[0054] 4, in the second driving method, the second motor 30 is not driven even when the test starts. That is, the nut 35 (second linear motion component) does not move in the axial direction. Therefore, when the nut 112 (first linear motion component) moves in the second direction X2, the gap between the nuts 35 and 112 becomes smaller.

[0055] In the second driving method, the nut 35 stops and the moving speed of the nut 112 does not change. Therefore, the ratio (proportion) between the amount of movement of the nut 112 in the second direction X2 and the amount of reduction in the gap between the nut 112 and the nut 35 is constant. In other words, the amount of movement of the nut 112 in the second direction X2 and the amount of contraction of the elastic body 45 are proportional to each other.

[0056] As described above, according to the second driving method, as shown in FIG. 5, the axial load increases in proportion to the increase in the stroke of the ball screw device 110.

[0057] (Third driving method of second motor) As shown in Fig. 4, in the third driving method, when the test starts, the output shaft 32 of the second motor 30 is repeatedly rotated forward and backward to move the nut 35 (second linear moving component) in the same direction as the nut 112 (first linear moving component). The moving speed of the nut 35 is constant. However, the moving speed of the nut 35 is set slower than that of the nut 112. According to this third driving method, when the nut 112 moves in the second direction X2, the gap between the nut 112 and the nut 35 becomes smaller.

[0058] Furthermore, in the third driving method, the speeds of the nuts 112 and 35 do not change. Therefore, the ratio (proportion) between the amount of movement of the nut 112 in the second direction X2 and the amount of contraction of the gap between the nuts 112 and 35 is constant. In other words, the amount of movement of the nut 112 in the second direction X2 and the amount of contraction of the elastic body 45 are proportional to each other.

[0059] From the above, according to the third driving method, as shown in FIG. 5, the axial load increases in proportion to the increase in the stroke of the ball screw device 110.

[0060] (Fourth driving method of the second motor) In the fourth driving method, once the test starts, the output shaft 32 of the second motor 30 is repeatedly rotated forward and backward, but the nut 35 (second linear motion component) is moved in the opposite direction to the nut 112 (first linear motion component). The moving speed of the nut 35 is constant. The moving speed of the nut 35 is slower than that of the nut 112. According to this fourth driving method, when the nut 112 moves in the second direction X2, the gap between the nut 112 and the nut 35 (second linear motion component) becomes smaller.

[0061] Furthermore, in the fourth driving method, the speeds of the nuts 112 and 35 do not change. Therefore, the ratio (proportion) between the amount of movement of the nut 112 in the second direction X2 and the amount of contraction of the gap between the nuts 112 and 35 is constant. In other words, the amount of movement of the nut 112 in the second direction X2 and the amount of contraction of the elastic body 45 are proportional to each other.

[0062] From the above, according to the fourth driving method, as shown in FIG. 5, the axial load increases in proportion to the increase in the stroke of the ball screw device 110.

[0063] As described above, according to the second, third, and fourth driving methods, when the amount of movement in the second direction X2 by the nut 112 (first linear moving component) increases, the axial load increases linearly (linearly).

[0064] According to the third driving method, when the nut 112 moves in the second direction X2, the nut 35 also moves in the same direction (second direction X2). Therefore, even if the movement amount (stroke) of the nut 112 is the same, the contraction amount of the elastic body 45 is small. In other words, the axial load is smaller than that in the second driving method (see when the stroke is S in FIG. 5).

[0065] Furthermore, according to the fourth driving method, when the nut 112 moves in the second direction X2, the nut 35 moves in the opposite direction (first direction X1). Therefore, even if the movement amount (stroke) of the nut 112 is the same, the contraction amount of the elastic body 45 is large. In other words, the axial load is larger than in the second driving method (see when the stroke is S in FIG. 5).

[0066] (Fifth driving method of the second motor) Fig. 6 is a graph showing the positions of the first linear motion component and the second linear motion component when the fifth driving method is implemented in the embodiment. Fig. 7 is a graph showing the relationship between the stroke and the axial load of the ball screw device when the fifth driving method is implemented in the embodiment.

[0067] In the fifth driving method, the second motor 30 is not driven before the start of the test. That is, the length L1 of the elastic body 45 is the natural length of the elastic body 45, and no axial load is applied to the ball screw device 110 at the start of the test.

[0068] 6, in the fifth driving method, when the test starts, the output shaft 32 of the second motor 30 is repeatedly rotated forward and backward, causing the nut 35 (second linear moving component) to move in the same direction as the nut 112 (first linear moving component). The moving speed of the nut 35 is slower than that of the nut 112. According to this fifth driving method, when the nut 112 moves in the second direction X2, the gap between the nut 112 and the nut 35 becomes smaller.

[0069] Furthermore, in the fifth driving method, the nut 35 decelerates as the amount of movement in the second direction X2 by the nut 35 increases. Therefore, the ratio (proportion) between the amount of movement in the second direction X2 by the nut 112 and the amount of reduction in the gap between the nut 112 and the nut 35 is not constant. In other words, the amount of contraction of the elastic body 45 is not proportional to the amount of movement in the second direction X2 by the nut 112.

[0070] As described above, according to the fifth driving method, the axial load increases exponentially as the stroke of the ball screw device 110 increases. According to this fifth driving method, when the amount of movement in the second direction X2 by the nut 112 (first linear motion component) is small, the axial load can be made relatively small.

[0071] Each driving method has been described above. The ball screw device testing device 100 of the above-described embodiment adjusts the magnitude of the axial load using the first motor 20 and the second motor 30, which can control the positions (rotation angles) of the output shafts 22, 32. This eliminates the need for expensive motors to achieve arbitrary torque control, thereby reducing production costs. Furthermore, by controlling the drive of the second motor 30, it becomes possible to adjust the axial load in accordance with the stroke of the ball screw device 110.

[0072] Although the embodiments have been described above, the present disclosure is not limited to the above examples. For example, the ball screw device test device 100 of the present disclosure may further include a reducer to increase the torque of the first motor 20 and the second motor 30. Furthermore, if the test is not for testing efficiency but for checking operation, such as whether abnormal noise occurs, or for evaluating durability, the ball screw device test device 100 does not need to include the torque sensor 23 or the load cell 47. Furthermore, a temperature sensor or the like may be further added to the ball screw device test device 100 to measure the temperature of the ball screw device 110 during testing.

[0073] In addition, in the embodiment, the screw shaft 111 of the ball screw device 110 constitutes the first rotating component, and the nut 112 constitutes the first linear component, but in the present disclosure, the screw shaft 111 may constitute the first linear component, and the nut 112 may constitute the first rotating component. Similarly, with respect to the load side ball screw device 33, in the present disclosure, the nut 35 may constitute the second rotating component, and the screw shaft 34 may constitute the second linear component.

[0074] Furthermore, although the end face 55 of the moving part 50 in the embodiment has the fitting portion 56 formed thereon, in the present disclosure, the end face 55 does not necessarily have to have the fitting portion 56 formed thereon. In other words, the end face 55 may be formed as a flat surface and may simply abut against the nut 112 (first linear moving part) from the second direction X2.

[0075] Furthermore, although the embodiment includes the elastic body support portion 37, the present disclosure may not include the elastic body support portion 37. That is, the elastic body 45 may be disposed between the nut 35 (second linear motion component) and the moving component 50, and both ends of the elastic body 45 may be in contact with the nut 35 (second linear motion component). Furthermore, although the present embodiment applies an axial load to the first rotating component (nut 112) via the moving component 50, the present disclosure may not include the moving component 50, and the elastic body 45 may be in contact with the first rotating component (nut 112).

[0076] FIG. 8 is a schematic diagram of a modified ball screw device testing apparatus viewed from a horizontal direction. The present disclosure may also be applied to a modified ball screw device testing apparatus 100A shown in FIG. 8. The modified ball screw device testing apparatus 100A does not have the elastic body support portion 37 and the moving component 50. Therefore, the end of the elastic body 45 in the first direction X1 contacts the nut 112 (first linear motion component). The end of the elastic body 45 in the second direction X2 contacts the nut 35 (second linear motion component). The method of fixing the elastic body 45 to the nut 35 (second linear motion component) is not particularly important. Even with this modified example, the cost of the ball screw device testing apparatus 100A can be reduced, as with the embodiment. Furthermore, by controlling the driving of the second motor 30, the axial load can be adjusted in accordance with the stroke of the ball screw device 110.

[0077] Furthermore, with regard to the fifth driving method, in the embodiment, the moving speed of the nut 35 (second linear moving component) gradually decreases as the amount of movement in the second direction X2 increases. However, the present disclosure does not require such a moving speed (deceleration). For example, the nut 35 may move a predetermined distance from the test start position while maintaining a constant first speed, and then move while maintaining a second speed that is slower than the first speed. In other words, the nut 35 may move at a relatively high moving speed at the start of the test and then at a relatively low moving speed thereafter. In this driving method, the moving speed of the nut 35 is set to two stages. As with the fifth driving method of the embodiment, when the amount of movement in the second direction X2 by the nut 112 (first linear moving component) is small, the axial load can be made relatively small. Thus, in the fifth driving method of the present disclosure, it is sufficient that the nut 35 (second linear moving component) decelerates when the amount of movement in the second direction X2 increases, and there are no particular limitations on the deceleration process.

[0078] Furthermore, with regard to the second to fifth driving methods of the second motor 30, in embodiment 1, no axial load is applied to the nut 112 at the start of the test, but in the present disclosure, the elastic body 45 may be contracted before the start of the test, and the test may be started with an axial load applied to the nut 112.

[0079] Furthermore, the driving method of the first motor 20 in the embodiment is an example, and other driving methods may be used. Furthermore, in the fourth driving method of the embodiment, the moving speed of the nut 35 (second linear moving component) is slower than that of the nut 112 (first linear moving component), but in the present disclosure, the moving speed of the nut 35 is not particularly limited as long as the nut 35 moves in the opposite direction to the nut 112. In other words, the moving speed may be faster than or the same as that of the nut 112. [Explanation of symbols]

[0080] 1 Support part 2. Actuator 3 Load device 4. Control section 20 First motor 21 Motor body 22, 32 output shaft 23 Torque sensor 24 Sensor body 25 1st axis 26 2nd axis 30 Second motor 31 Motor body 33 Load side ball screw device 34 Screw shaft (second rotating part) 35 Nut (second linear motion part) 36 Load side support part 37 Elastic support part 38 Main body 39 Rod 40 flange 41, 51 Linear guide 42, 52 rails 43, 53 slider 45 Elastic Body 47 Load Cell 50 Moving Parts 55 End face 56 Fitting part 100, 100A Ball Screw Testing Equipment 101 Base 102 Installation surface 110 Ball screw device 111 Screw shaft (first rotating part) 112 Nut (first linear motion part)

Claims

1. a support portion that rotatably supports one of a screw shaft and a nut of a ball screw device to be tested, and that linearly supports the other, a first linearly moving component; a first motor that is disposed in a first direction, which is one of axial directions parallel to a central axis of the screw shaft when viewed from the support portion, and that generates torque to rotate the first rotating component; a loading device that is disposed in a second direction, which is the other of the axial directions, as viewed from the support portion, and that abuts against the first linear moving component and applies an axial load to the first linear moving component; Equipped with The load device is A second motor; a load-side ball screw device including a second rotating component that rotates by torque generated by the second motor and a second linear component that moves linearly due to the rotation of the second rotating component; an elastic body interposed between the first linear motion component and the second linear motion component; Equipped with The first motor and the second motor have controllable output shaft positions. Test equipment for ball screw devices.

2. the load device has a moving part that is arranged movably in the axial direction and abuts against the first linear moving part from the second direction, The moving part is biased in the first direction by the elastic body. The testing device for a ball screw device according to claim 1.

3. The load device has a linear guide that supports the moving part so that the moving part can move in the axial direction. The testing device for a ball screw device according to claim 2.

4. the load device has an elastic body support portion that supports the elastic body, The elastic body support portion is a main body portion connected to the second linear motion component; a rod supported by the main body portion so as to be freely movable and having a flange formed on an end portion in the first direction; and The rod penetrates the elastic body, and the main body and the flange sandwich the elastic body in the axial direction. The testing device for a ball screw device according to claim 3.

5. a control unit that controls driving of the first motor and the second motor, The control unit controlling the driving of the first motor so that the first linear moving component moves in the axial direction at a constant speed; Controlling the driving of the second motor so that the second linear moving part moves at the same moving speed as the first linear moving part and in the same direction as the first linear moving part. The testing device for a ball screw device according to any one of claims 1 to 4.

6. a control unit that controls driving of the first motor and the second motor, The control unit controlling the driving of the first motor so that the first linear moving component moves in the axial direction at a constant speed; Controlling the driving of the second motor so that the second linear moving part moves at a constant speed and at a moving speed slower than that of the first linear moving part in the same direction as the first linear moving part. The testing device for a ball screw device according to any one of claims 1 to 4.

7. a control unit that controls driving of the first motor and the second motor, The control unit controlling the driving of the first motor so that the first linear moving component moves in the axial direction at a constant speed; The drive of the second motor is controlled so that the second linear moving part moves at a constant speed in a direction opposite to that of the first linear moving part. The testing device for a ball screw device according to any one of claims 1 to 4.

8. a control unit that controls driving of the first motor and the second motor, The control unit controlling the driving of the first motor so that the first linear moving component moves in the axial direction at a constant speed; controlling the driving of the second motor so that the second linear moving component moves in the same direction as the first linear moving component at a moving speed slower than that of the first linear moving component; Furthermore, the second linear moving component decelerates as the amount of movement in the second direction increases. The testing device for a ball screw device according to any one of claims 1 to 4.

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